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My Fostex R8 Machines
I own two machines of this type. To my disappointment as of early 2012 both were defunct and some tape transport functions have become
completely unusable. The tape deck from the rehearsal room (serial no 0600838) appeared to be in a slightly better shape than the one in the music
studio (serial no 0605030) (Andreas' Music Studio - #FostexR8). I therefore decided to fix the former first. Having read many fora on the internet and
finally found the excellent site by Dr ZEE MZE-Electroarts Entertainment - MZEntertainment.com: Dr. ZEE WORKSHOP FOSTEX R8 Analog ReelTo-Reel multi-track Tape Recorder I was sufficiently encouraged to try the repair instead of the discard route.
Fostex R8 Repair •• (formerly rehearsal room machine)
I followed the instructions to remove the front cover as described in FOSTEX R8 Repair PROJECT - [PART-1]REMOVING COVERS - ACCESS FOR
SERVICING and REPAIR by Dr ZEE. All worked as explained there, except for following issues I encountered: The main front cover (hold by 6
screws), albeit loose once its holding screws are removed, can not really be removed. This becomes only possible if also the central, separate cover
part protecting the heads is removed too (hold by 2 screws, see picture):
Once all open, indeed I found that the tape take up reel motor pulley (top right seen from front) had a small crack. I could remove the pulley by sliding
it up (with the belt on it). Then I cleaned the pulley in alcohol, cleaned the shaft too and made a few cracks/dents into the shaft using a wire cutting
plier (I did this according to the advice I got from a repair expert at Audio Bauer Pro AG, Zurich). Then I put glue (Araldit standard) into the middle hole
of the pulley, helping the glue to really get into the entire length of the hole by using the wire from a paper clip to push the glue all the way down and
spreading it out to all surfaces of the hole. Then I put the belt back on the pulley and gently pressed the pulley back onto the shaft till the belt was
horizontal (leveled with take up reel and that belt becomes parallel to mounting surface of deck's chassis). While pressing the pulley onto the shaft
some glue was pushed all through the pulley but none touched the shaft's base, let alone the motor's top. I let this dry for 24 hours before
reassembling the unit.
Some snapshots from the repair:
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Note, the short screws of main cover are at the bottom. The washers are used just below the heads of the screws. There is also a washer on top of
the pinch roller, i.e. it comes between its cap.
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Only when also the central cover is unscrewed can the entire front cover be removed (later on I figured out that FOSTEX R8 Repair PROJECT [PART-1]REMOVING COVERS - ACCESS FOR SERVICING and REPAIR in another part of the document explains this too). When reassembling,
don't forget to do it in reverse order, i.e. put the front cover on first and attach the central cover last.
Testing the unit:
Indeed, on 19.May.2012 I tried the tape deck and it seems to work again. I cleaned the heads with Isopropyl-alcohol. They were very, very dirty (the
unit was used without my permission by Walti Reist's son, who obviously has not bothered to clean the heads). First tests were done in horizontal
position: Playback looks very good, only fast forward and fast rewind seem to be a bit slow, in particular towards the end of the tape. However, after
several uses all seemed to get back to normal speeds: Fast forward, rewind, and playback was fine. Second tests were done in vertical position:
Playback no longer works but stops by itself shortly after having been engaged. A pity. Fast forward and rewind seem to work very well now. Is it a
slacking tape that triggers the playback to stop? Perhaps some adjustments could be made to prevent this.
Since I plan to put the unit into the rack to replace the previously used unit while swapping the MTC-1, I have to ensure that playback works in the
vertical position too or I can't mount the unit in the rack.
I wrote to Dr. Zee and got an answer. However, he has no idea what the reasons might be. Considerably later I figured out what the problem with the
playback was: It was only present if the cover was not on the machine. Then the machine has a slight tilt forward in vertical position and reels are not
really vertical. Therefore it was possible that the take up reel, which is more lose than the left reel could slightly glide forward and interrupt the light
bridge. This made the playback stop shortly after engaging, typically just after 2 seconds. With the cover on the machine is actually vertical and the
take reel no longer glides that much forward and is kept in position by the belt and the position of the motor pulley.
I encountered several times that after putting the cover on and connecting the remote control that all sorts of LED's were suddenly lighted with no
obvious reason. Tracks were activated for recording etc. The first time I observed this the remote control was completely non-responsive and I could
not issue any commands. I then removed the cover once again and no sooner had I done that, all was back to normal once turned on. After the final
attempt to put the machine back together again I observed again very strange LED's lighing up. But this time the remote control responded and I
could at least disengage all the turned modes, preroll etc. I manually turned all these modes and preroll time of to get the wanted state of the machine
back. Once that state was set, turning power on and off made no more any difference. I did not try the button on the top of the machine labelled:
Reset Memory. Perhaps that would have helped too. At least the machine seems now to be ok.
Finally there is a problem with the right tension roller. First the part of the cover seems to have been lost and there is (now?) a hole in the cover.
Secondly the shaft of the tension roller does not come out sufficiently. Therefore putting the cap onto the roller according to the normal assembly
results in the tape beeing pushed away from the take up reel and the tape touches the reel all the time producing also a lot of noise. I therefore did
not put the cap onto the tension roller, since I saw not easy way to make the shaft stick out further without having to remove the cover once more.
Other than these minor issues left the Fostex R8 is now fully functional again and I hardly notice any major glitches anymore. Rewind, fast forward,
play back, locating previously stored positions, all work fine. However, I have not tested recording.
Heads need to be cleaned very often with a Q-tip and Isopropyl-alcohol. Playing one tape is sufficient to have them covered by ferromagnetic
material.
Dark side of tape is on the outside, the lighter, brownish side is the one which should glide over the heads.
af, 17.May.2012, 19.May.2012
I take the Fostex R8 (studio machine) out of the rack and swap the MTC-1 from that machine to the repaired one. The goal is to test whether it is
possible to sync the now repaired Fostex R8 with my main sequencer Logic 9 (Logic Studio) using the new MIDI interface "MOTU midi express XT".
First, the Fostex R8 seemed to work fine after having connected it to the new MIDI interface. I used a good audio cable to connect the track 8 output
with the SMPTE IN port on the MIDI interface and y-ing the same signal to the MTC-1's LTC IN port. I also connected the MTC-1 to the MIDI In and
Out ports on the MIDI interface. All connections as described in the wiring diagram at
Andreas' Music Studio - #Studio4.
Playing back a striped tape I could observe in the applications ClockWorks or Logic the proper time code (given I used a tape with a strong enough
signal on track 8, e.g. Tape B (Tape A has a too weak signal and many drop outs result which leads to erratic, jumpy behavior of the display in
ClockWorks as well as Logic).
Unfortunately the remote control often behaves strangely. It suddenly does no longer obey any commands, e.g. after switching to the remote control
from the other Fostex R8. Memory Reset on the top of the tape machine seems not to have any effect. At least no position settings are forgotten by a
power cycle or even when disconnecting the power cord of the unit from the power outlet. Perhaps this memory feature of this 2nd Fostex R8 is
playing a bit havoc. I also previously had a similar problem with an irresponsive remote control. Removing the front cover helped to suddenly have
this problem being gone. Maybe the battery is no longer very good and the unit's functioning suffers. Having had disconnected the machine from the
power outlet for an hour or a bit more was sufficient to regain control over the unit via remote control and then also MMC. The latter is indeed
probably the cause of all these difficulties I encountered. I learned later also that I had performed the memory resets incorrectly. The instructions that
came with the battery backed up memory extension, which I found again and consulted finally, tell clearly that a reset works only if the power is
switched from off to on while depressing the reset button. Performing a memory reset in this manner now helped always to overcome erratic behavior
of the remote control.
I also encountered another difficulty: I did not manage to control the unit via MMC. I tried several configuration of ClockWorks's routing and other sync
settings. E.g. both following routings showed no difference:
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However, I once managed to make the Foster R8 start playback when clicking the play button in Logic. All settings were made as before in the old
music studio, i.e.
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I also tried the default MMC ID 19 recommended by MOTU in the MIDI interface manual, but to no avail. With the one single exception no response
to MMC commands, regardless wether "Old Fostex format" or "MMC standard messages" mode were used. Setting all preferences exactly as
described in the document 'My Music Studio (OS X 10.4.11).dock' was finally sufficient to get MMC working fine. The additional project specific
settings were "Transmit MTC" , "Transmit MMC", and "Listen to MMC". These are the settings where MMC works:
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With these settings it was even possible to MMC a cycle in Logic. The only difficulty I encountered was that the tape seemed to get worn out slightly
and twice it even turned between the reels, so that the back of the tape glided along the heads while it was properly taken up by the reels on both
sides.
However, syncing is now bad, i.e. intermittent locking and I get the same problems as I got with Tape A, despite the fact I have cleaned the heads and
made otherwise sure all is fine. The signal from track 8 looks now similarly weak as that from Tape A. Track 8 playback of the time code signal seems
not to work sufficiently reliably and I get regularly dropouts causing very variable song speed. I am not sure whether this is a track alignment problem,
meaning that I should restripe the tape. Difficult to say, since restriping the tape in case of bad head alignment might cause difficulties, since some of
the old time code signal might remain on the tape and continue disturbing the playback.
I have restriped the uncritical Tape B using ClockWorks and made sure signal levels were at -3VU as described on p. 58ff. in the MOTU midi express
XT manual. Then playing the tape back resulted in a perfect lock according to ClockWorks with no drop outs. All Status lights are continuously yellow
during tape play back (Sync tab in ClockWorks). A sharp contrast to the previous experience.
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Unfortunately, the time code signal gets weaker and weaker quickly (first playback -7VU, then -10VU). Perhaps this is due to tape wear out, since
tape seems to get somehow warped such that the front edge becomes wobbly. This seems to be due to some mechanical tape transport stress. This
happens in particular during quick rewind and playback transports as typically taking place during a cycle. Longer playback seems to stabilize tape
transport which then gets smoother and makes much less noise.
However, when using also Logic, syncing was still bad, i.e. the song position pointer erratically jumped back and forth as it has been doing before.
Thus it seems the bad sync was not only the result of a weak time code signal. The following routing fixed this, i.e. adding connection from MTC-1
MIDI OUT to MTC of the MIDI interface:
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Now the sync seems to be perfect. The song position pointer moves steadily, ClockWorks shows continuous perfect sync. Moreover, with a "Software
Instrument" in Logic all sounds now fine and the rhythm is steady. I have not tested it with analog recordings, but expect now no more surprises. Also
MMC seems to function perfectly. I can move the song position pointer to any location and the Fostex R8 follows (just give it sufficient time to really
do it before clicking play). Again quite a nice setup.
Cable connections are: MIDI connections both ways (Port 1). All LTC signal cable connections, i.e. track 8 output connected to LTC IN on the MTC-1
as well as the SMTPE In on the MIDI interface (cf. wiring diagram at Andreas' Music Studio - #Studio4). I experimented with disconnections:
1) Separating the P8 -> SMTPE IN results in sync loss. Thus the LTC signal has to arrive at the MOTU midi express XT's SMPTE IN port to then be
sent to the computer for proper syncing.
2) Separating P8 -> LTC IN MTC-1 seems first not to matter. Even the remote control if counter is first reset and the played back, immediately jumps
back to the correct display according to the recorded time code signal. However, if the counter is reset after a power cycle, then the remote control
display shows a wrong time and not the striped time. Only if that connection is present, does the remote control show the proper time. This
connection is therefore always required.
3) Separating MIDI OUT MOTU express XT -> MIDI IN MTC-1 matters. Any MMC commands are no longer effective as was expected. However, this
seems not to matter for the position display on the remote control. Therefore no MTC code seems to be sent to the MTC-1 through that connection
and what matters for that is only connection 2). It seems also that no MMC confirming messages are sent through that cable, since all transport
commands issued in Logic (all buttons Play, Stop, Pause etc.) work regardless of this connection. Also song position pointer moves result in the
wanted positioning of the tape. Here only make sure you don't rush and give the machine sufficient time to respond properly. Very nice.
4) Separating MIDI OUT MTC-1 -> MIDI IN MOTU midi express XT seems not to matter. The latter is hard to understand, since I needed to route
MIDI port 1 (Fostex R8/MTC-1 on the left) to MTC (on the right) of the MOTU express XT to get the sequencer to sync fine. It seems to me, that
would require this connection to matter. Maybe this actually interrupts something, such as sending an additional MTC code to the sequencer, than
adding an additional routing. I don't quite understand this and my attempts to study the manual have not really clarified this. Perhaps I should contact
MOTU and ask for an explanation to be on the safe side. Moreover, possibly connecting the MTC-1 to MIDI port 8 (on the back only output, but no
input) would free up MIDI port 1 for another use and still give me flexibility to connect the GR-1 from the front when not simultaneously using the
Fostex R8. On the other hand I have now no shortage of MIDI ports, since Port 3 (formerly QY20) is also no longer in use.
I did some further testing, i.e. routing another MIDI IN port, GR-1 MIDI Guitar (left) to MTC (right). This resulted in very bad syncing in the sequencer
only (ClockWorks shows no sync problems). Logic's song position pointer jumps back and forth erratically. Disconnecting the MIDI connection from
the MTC-1 to the MIDI interface then removes that problem and Logic syncs again fine. Then I discovered that while having no routing present from
Fostex R8/MTC-1 (left) to MTC (right) that this synced also fine to the sequencer when disconnecting P8 -> SMPTE IN. This all means that the erratic
sync behavior is the result from conflicting MTC signals arriving at the same time from the MTC-1 and the MIDI interface. The routing Fostex R8/
MTC-1 (left) to MTC (right) seems therefore to prevent the MOTU midi express XT to send MTC to the sequencer and instead routes the signal from
the MTC-1 simply to the computer, i.e. the sequencer. ClockWorks also shows the proper position, since it only receives it, locks to it perfectly, but
does not send it out to the computer. It seems that when the MIDI connection from the MTC-1 to the interface is not present, it does not matter
whether the routing Fostex R8/MTC-1 (left) to MTC (right) is present or not. The interface seems to generate the MTC code anyway as long as it
receives LTC on its SMPTE IN port. I believe now no routing means the MTC messages are sent to the computer directly. When routing is present
they are intercepted by the MIDI interface. However, which MTC is actually sent to the computer is not clear to me. The one received from the MTC-1
is forward unmodified to the computer or simply swallowed and a new one generated by the interface from the LTC received on the SMPTE IN port? I
tried a test where I attempted to remove the routing MTC (left) to the computer (right). ClockWorks 1.6 49342 ignores the removal of that routing, e.g.
via backspace in contrast to all other routings. Therefore I guess what the routing from Fostex R8/MTC-1 (left) to MTC (right) means is simply,
swallow the MTC code generated by MTC-1. Moreover, having the proper routing and the critical MIDI connection present, but disconnecting the LTC
signal from arriving at the SMPTE IN port disrupts any syncing. Not quite true. In MTC mode it becomes possible to reroute the MTC code received
from the MTC-1 even if there is no LTC arriving at the SMPTE IN port. Avoiding that routing means the MTC code as generated from the MTC-1 is
arriving at the sequencer, but ClockWorks no longer syncs and displays nothing useful. Only if I add the routing from Fostex R8/MTC-1 (left) to MTC
(right) do I get again a sync.
Conclusion:
Omit MIDI connection MIDI OUT MTC-1 -> MIDI IN MOTU midi express XT or if in LTC QuikLock (or LTC) mode make sure MTC-1 generated MTC is
swallowed by the MIDI interface by the appropriate routing. If using MTC mode that same routing is also useful in order to see in ClockWorks the
position (remember MTC code is always going to the sequencer if the MIDI OUT connection from the MTC-1 is present; the routing only controls
whether the MTC code is arriving at the interface (routed to it) or not).
I have now been able to use the repaired Fostex R8 as sync master and MMC slave, while connecting it via the new MIDI interface "MOTU midi
express XT" and using my new Mac mini under Snow Leopard and the latest Logic sequencer as sync slave and MMC master. The only thing which
did not work, was to record-enable or disable tracks on the Fostex R8 via the sequencer, despite having “Transmit Record enable commands for
audio tracks” setting active. With this option according to the Logic manual (Logic Pro 9 User Manual: MIDI Preferences in Logic Pro), MMC Record
Enable/Disable commands are sent out when audio tracks are record-enabled (armed) or disabled. In addition, any received MMC Record Enable
commands should also set the record-enable status of audio tracks in the sequencer (which would certainly require the "green connection", cf.
Andreas' Music Studio - #Studio4).
Hint: To force a rereading of the position from the time code recorded on the tape as shown on the remote control after a power cycle to, it is best to
cause first a tape error by giving the tape sufficient slack. Then resume normal operation and the remote control should now also show the actual
time code from the tape.
The LED "NR OFF" on the remote control of the repaired Fostex R8 does not work anymore. The remote control of my studio Fostex R8 • is without
fault and can also be used on the now repaired Fostex R8 ••. I have also a service manual that tells that pressing the STOP button while powering on
does test all LED's (LED Check Function Mode).
The only difficulty really remaining is the tape transport stress and the turning upside down of the tape in cycling mode of Logic. The Fostex R8 •• is
obviously not in perfect shape. I will therefore also try to repair my other Fostex R8 I previously used in my studio (Andreas' Music Studio #FostexR8).
af, 26.May.2012
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Fostex R8 Repair • (Studio Machine)
Removing the top cover revealed that the take up reel motor pulley (top right) was come off entirely its shaft. That pulley also has a tiny crack. I
detected that the motor pulley from the supply reel (top left) is already repaired with glue. It looks like the glue used was Araldit. This detection was a
bit of a surprise, since I do not remember having been informed about this, neither by the previous owner nor the service men who have repaired and
serviced this machine. The capstan motor pulley seems to be ok at least could I not see any cracks nor does it appear to rub against the chassis.
af, 3.Jun.2012
Cleaned the shaft and take up reel motor pulley (top right) with alcohol and "mistreated" the shaft with strong pincers carefully around the entire shaft
and roughened the shaft further with sand paper. I did sanding very carefully and only while the machine was in vertical position (shaft in horizontal)
to avoid any sand particles to fall into the machine. Finally I vacuumed the shaft and its motor thoroughly once I was done with sanding. In particular
the sanding seemed to have roughened the shaft considerably according to the touch by fingers. I then of course cleaned the shaft once more with
alcohol. Then I applied the glue carefully by first inserting glue using a bended paper clip wire into the pulley's axle hole and otherwise generously, in
particular also around the entire exterior of the pulley bottom shaft where the crack was. I mounted the pulley while making sure to get perfect
alignment so that the transport belt is perfectly parallel to the chassis. Final checking of glue being generously spread at the top of the pulley to
ensure the shaft's top bonds well with the pulley.
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af, 4.Jun.2012
I let the glue dry for almost two days. I try out the repaired Fostex R8, and indeed, it works almost like a charm. Its tape transport is considerably
better than that of the machine I repaired first and works generally very smooth. No tape strain. Moreover, heads playback recordings, notably the test
tones, also much better and more precise than the other Fostex R8.
All seems quite fine except occasionally I get a chirping loud noise when playing the tape back. The noise seems to come from the pinch roller.
However, this is not always the case and seems to vary a lot. I am not sure whether these symptoms are the ones described by Dr Zee FOSTEX R8
Repair PROJECT - [PART-3]FIXING CRACKED CAPSTAN and REEL MOTORS PULLEYS. He attributes that noise to the capstan motor plastic
pulley moving up on the shaft and rubbing against the metal chassis. I have to check for that more closely.
af, 6.Jun.2012
Playing back some recordings revealed that whenever I hear the chirping sound the tape does not playback at ordinary speed, but is slower than it
should. This indicates clearly, I have a problem with the tape transport for playback. A close inspection of the capstan motor pulley, however, did not
show any cracks nor otherwise does the pulley seem to have come loose and is certainly not rubbing against the chassis. However, it is very difficult
to see whether the shaft is slightly not having full traction. Moreover, each starting of playback from a stop results in the chirping sound and a too slow
tape transport. Perhaps it is the capstan belt that causes this problem. Or the flywheel needs some oil?
af, 6.Jun.2012
I phoned the expert, Mr. Oros, at Audio Bauer Pro AG, Zurich once more. His guess was that the chirping noise would not come from a loose capstan
motor pulley (unless it would rub against the chassis), but from the capstan belt. He recommended to send the old to me so that he can ensure he
finds a correct replacement.
The Fostex R8 •• repaired first (see top) does also make often chirping noises. I therefore opened that Fostex R8 from the back according to the
instructions of Dr. Zee (FOSTEX R8 Repair PROJECT - [PART-1]REMOVING COVERS - ACCESS FOR SERVICING and REPAIR and FOSTEX R8
Repair PROJECT - [PART-2]REPLACING CAPSTAN BELT / REMOVING CAPSTAN MOTOR and PULLEY). All worked well except recovering the
screws from the capstan flywheel mounting bracket once unscrewed was very difficult and two screws fell off and I "lost" them to the lower chamber
of the machine. There are many holes in the chassis part separating the two chambers. I should have better put first some paper there to cover the
holes before starting to unscrew. I hope it will not be too difficult to retrieve the two "lost" screws. Having now access to the flywheel it seems clear
that the flywheel itself is not causing the chirping noise, since it turns in its place very smoothly.
I opened also the front cover having temporarily reattached the back with two screws and putting the machine with its back on two large, thick books
on each side. I detected the missing screws in the lower compartment between the track boards and could retrieve them thanks to a pair of very long
tweezers without having to remove any of the 8 track boards.
af, 7.Jun.2012
I received finally two new replacement belts for the capstan motor from the specialist at Audio Bauer AG. For free, very kind. I again decided to first fix
the first Fostex R8 •• (formerly rehearsal room machine).
I did put two pieces of paper into the machine to catch any dropped screws should I lose them during mounting. I cut an A4 piece of paper into half
(lengthwise) and then halfed that stripe once more to be able to put into the Fostex. With these two pieces of paper I could cover most of the holes
through which a screw could disappear into the lower compartment where retrieving it would be a hassle.
I then cleaned both wheels, the motor pulley as well as the big heavy flywheel. Then I mounted the belt and the capstan motor bracket by screwing it
on. I used some adhesive plaster, resembling chewed chewing gum, to hold the screws to the screwdriver to not lose them too quickly while mounting
the racket (same adhesive plaster used for mounting posters to the wall without needing a nail). First I lost only once a screw and could easily retrieve
thanks to the paper. Second I had the racket mounted rather easily, first the top two screws, then the bottom two. Then I reconnected the electrical
wire connector of the capstan motor bracket to the board and closed all up by screwing the top-back control board / inputs-outputs block.
I tested tape transport before closing up anything. I adjusted there also the tape tension / guide arms rollers axle by ensuring the tape is guided
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properly in the middle of the reels. That was easy once the screw at the side was a bit loosened and then retightened once the tape guides were
guiding the tape at the proper distance. The machine is now also transporting the tape very well and much smoother than before.
Then I reassembled the entire machine by first mounting the front cover (resting the Fostex onto two books on the sides), then the head protecting
central cover and finally the back plus screwed the handle back on. Finally I mounted all tape guiding parts to complete the assembly.
The machine worked considerably better. However, at the begin of a tape I hear still some chirping noise and the tape does not gain full speed right
away. The acceleration delay is not big, nevertheless it is clearly there. Not so towards the end of the tape. In the last third the machine works
perfectly. Starting playback engages the tape immediately, no chirping noise and the tape is transported at the proper speed right away. That is the
functioning as I am used to from earlier times. I wonder, whether the motor pulley is not partly lose and is causing this chirping noise when there is too
much load (at the begin of the tape) to transport. But other than that this Fostex R8 is now really in good shape again.
af, 14.Jul.2012
Continued working on this machine by removing the back cover and accessing the capstan motor to exchange the belt and check whether the pulley
sits really tight on its shaft as I suspected giving the chirping noise that the machine makes when starting playback or the speed-up behavior that
takes place during this noise making. Indeed, the pulley does not sit tight on the shaft as I notice when gently but firmly trying to move the pulley
outwards away from its shaft using a broad screwdriver. The pulley comes easily lose from its shaft and was clearly no longer holding well to its shaft
during playback or recording:
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Therefore it needs glueing on as this was the case with the other pulleys. Note also I see no cracks in the pulley as e.g. shown in FOSTEX R8 Repair
PROJECT - [PART-3]FIXING CRACKED CAPSTAN and REEL MOTORS PULLEYS, even if look through a magnifying glass. Glueing it on and
making sure it does not touch the chassis and is leveled as described by Dr. ZEE:
See also the glue pile on the top of the pulley that was pressed out (should not matter, since center of pulley is vis-a-vis the hole in the chassis and
only outer rim of the pulley can touch the chassis if coming off the shaft. However, underneath the pulley I see no glue, despite I have all glue first of
all applied into the pulleys shaft hole from underneath. Pressing the pulley onto the shaft must have avoided any squeezing out of glue there. But I do
not dare of applying any since I might too easily make a mess there and having applied and distributed the glue really well inside the pulley's hole I
guess that should do.
Thus my hope is that fixing the pulley with glue permanently onto its shaft together with replacing the belt I should get my studio machine back in
nearly mint order. Will see once the glue has dried and all has been reassembled.
af, 24.Aug.2012
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Checking out the motor capstan pulley 24 h later shows that the glue pile is still soft and can flattened if gently pressed. I found some information on
Standard Araldit saying that getting the glue totally cured may require 72 h at room temperature (see nearby pdf). However, the same source states
that component A remains fine for 6 a and component B for only 3 a. I am not sure how old my Araldit is, but it may well be it is older than 3 a. I hope
the glue is still good enough and that waiting a bit more will help to get all really cured throughout and a tight bond between shaft and pulley.
That same source also states that higher temperatures can considerably speed up curing. Thus I repeatedly warm the pulley and its shaft every hour
or so using a hair blower.
af, 25.Aug.2012
The top is still not cured completely. I have nevertheless decided to reassemble the machine. Once I had the motor mounting bracket in place I gently
moved the flywheel to make sure the belt is in its correct position. A heard an annoying noise from the belt rubbing on something instead of smooth
movements of the drive mechanism. I feared first the belt rubbed on the chassis, since the replacement belt is slightly wider than the original one.
Fortunately it turned out I had merely fooled myself by not yet removing the sheets of paper that I had inserted to prevent any screws from falling
down into the interior of the machine. That paper at the bottom of the motor mounting bracket was wide enough to rub on the belt and produce this
ugly noise. Once I had that paper sheet removed, the belt moved very quietly as it should and all seems to be fine now. The machine is now
reassembled and awaits its testing.
Unfortunately first tests are very mixed. Partly the machine works flawlessly, partly I hear the same chirping noise when starting playback as I heard
before, and twice all playback stopped even entirely, i.e. the flywheel axle turns, it seems as it should, but the tape and the reels don't not move
anymore at all, as if all would be blocked. Winding forward or backward a bit removed this "blocking" and I could use the machine again, even in
some instances starting playback and no chirping noise was audible. Narrowing down those instances with the problems means a max difficulty is
encountered whenever the tape is about one third off. That is when the right take up reel has a rather large leverage because the diameter of the
taken up tape has gotten larger while the weight of the tape on the left side is still rather big. Once half of the tape has come off the left side, the
weight of that tape is reduced and despite the leverage even having grown more, the reduced tape seems to make it very easy for the tape to gain
speed and I never heard the chirping noise at the begin of playback in the 2nd half of the tape. These tests concerned only mechanical functioning
and I did not yet listen to the actual playback of audio from the tape.
af, 28.Aug.2012
Have removed the capstan motor from the Fostex R8 •• (formerly rehearsal room machine). Again also there the pulley was easy to remove from its
shaft. I roughened the shaft with files, cleaned all with alcohol, and glued the pulley back on using Araldit Rapid. That glue is date-wise still ok and my
inquiries on the internet as well as at our drug mart resulted in that there should be no difference in terms of binding between Araldit Standard and
Rapid. Only the time window left to glue things together differs.
af, 7.Sep.2012
Have mounted the newly fixed capstan motor into the Fostex R8 • (studio machine). The result is unfortunately not that much different. While
transport works basically fine chirping noises are occasionally to be heard. However, in contrast to the experience with the previous capstan motor, I
observe phases, during which the playback starts immediately without producing any chirping noises. In other phases I get a lot of those chirping
noises. It seems also that the behavior depends on the actual tape in use.
Having no tape on the machine but emulating the presence of a tape by lifting one of the tension arms lets me test the functionality of playback, fast
forward and rewind. It seems all these functions work perfectly fine and no noise can be heard when no tape is present. Fast forward means only the
right take up reel winds. Fast rewind means only the left supply reel winds. Playback means both reels wind, by the way surprisingly fast. In all these
cases no special noises can be heard and for sure no chirping noise.
I observed that the chirping noise is coming from the left reel. I can also easily produce the chirping noise by slightly holding back the left supply reel
during playback with a finger gently pressed against its rim. Perhaps the left pulley does really not sit that well anymore on its shaft. However,
inspecting that connection lets me not see anything loose. Moreover, trying to lift off the pulley with a screwdriver is not possible and it seems to sit
quite tight. However, being only a bit loose may suffice to occasionally produce those chirping noises. When a tape is actually mounted, I found it also
surprising how heavy that tape's mass is and that moving it requires probably considerable forces. That may also explain why during playback without
an actual tape mounted, the reels turn with as high a speed as during fast forward or rewind.
af, 10.Sep.2012
I had finally some idea how one can reliably test whether a pulley sits tight on its shaft: I marked with a felt pen the shaft and the pulley at the same
spot on its rim. If the pulley sits not tight, the probability is very small that they will line up. I tested this with the left and the right reel and encountered
many times the chirping noises. However, the line up never changed a bit. Thus I conclude that the supply as well as the take up pulleys sit tight on
their shafts and my suspicion it could be that must be wrong. But for sure it remains that the chirping noise comes from the left side of the machine. I
now also noticed that I can produce the chirping noise by slightly holding back the electronic counter roller. Moreover, I several times noticed that fast
forward failed completely, unless I loosened somewhat the left reel. Like a brake would block it. I observe this problem only in the 2nd half of a tape.
Perhaps it has something to do with brake adjustments or is it the transport control mechanism motor? Unfortunately I could not find anywhere
anything on this topic on the internet. (A generally not too bad website, at least for repairing some tape machines, is http://wn.com/fostex_r8)
af, 16.Sep.2012
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