• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Fixing up a CT-F9191

V

voxswain

Member
Just picked up a nice looking CT-F9191 that I'm going to restore. It's not currently playing - it turns on and lights up, tape spins, but no sound to line out or headphones. The first thing I'm going to try is deoxing the two switches in this thread. Deoxit will arrive from Amazon on Thursday. The rewind is slow, too - does my diagnosis of a bad idler seem correct? Far as I can tell, MTF is still doing those, so I'll probably have to send that out.

In the meantime, I'm looking into replacing the belts. Seems like the WJOE kits are the most widely accepted ones, so those are what I'll pick up, but I'm a little confused on what I actually need to buy. I see both the "CT-F9191 Belt kit" and the "CT-F9191 Rubber Pulley Kit". Do I want both? This post makes me think there's 3 belts, but I'm thinking the 3rd belt referenced might be the pulley. I'd appreciate some clarification as to what I need.

Finally, once I get it all working again, is there any standard practice for maintenance? I'm hoping to hold onto this thing for a while, so anything I can do to lengthen its lifespan would be great. I was thinking a recap might be in order (if not for the deck, then for me to have something to do ;)). Haven't been able to find a good list of new parts to use, so I may need some assistance building one out. I'm guessing I'll also want to calibrate; I've got access to a multimeter, but no scope or calibration tapes right now. Guess we'll cross that bridge when we come to it.
 
Register to hide this ad
Sounds like you are on the right path. I just worked on a CT-F8282 and the 2 solenoid operated switches were dirty and causing issues with the sound and the VU meters going crazy. All that was solved with a cleaning of the switches and the pots. The belts to the motion sensor and counter are worn out and slipping causing it to stop play after 3 seconds. I’ve gotten the belt kits from WJOE. I’ve gotten the drive tire from him too but not needed it.i would inspect yours first before ordering the tire. I would suspect that the rewind issues are from the clutch and Mark is still doing them. I just contacted him. I’m waiting on a 3rd deck to arrive this week and I’ll be sending him all 3 clutches at once. I would have the clutch done whether it’s failed yet or not.
 
ive done a few ct-f750's and i use wjoe for the belt kits...always been good for me! i had some tire issues and i just removed them and switched sides left to right don't know why it worked (uneven wear maybe) but it did..:)
 
Thanks all, glad to know I'm on the right track with the WJOE kits. Good idea switching the tire locations, I wouldn't have thought of that. I may end up replacing them anyway if it's not too expensive, since I don't think new rubber would hurt. I went ahead and cracked open the top:
photo_2020-10-14_08-27-57.jpg
I can see three belts in this picture: the first thin one, sort of in the middle on the left, controls the tape counter (which doesn't currently work). I believe the other thin one, which looks to be on the same axle as the first, is connected to the spindle that slots through the tape (unsure of terminology). The giant belt on the large metal wheel is connected to the capstan - I'm guessing that's the "rubber pulley" I referenced earlier. Can anyone confirm? I'm curious as to what's up with the counter, too; turning the wheel manually doesn't appear to make it count, so I'm not sure the problem is just a bad belt. I wonder if it just needs a little oil or something.
 
Hello, the rubber pulley is located at the end of the shaft of ffwd and rewind motor. It looks similar to the eraser on a pencil. The rewind motor is all the way at top of your photo above the wiring. The rubber pulley drives the clutch. When the clutch locks up that rubber pulley can get worn from slipping on the locked up clutch. The larger belt in the photo would not be the rubber pulley. The longer of the smaller belts In the picture drives the motion sensor and then in turn a smaller belt runs from the sensor to the counter. If the counter doesn’t work with the counter pulley turning then the tape counter is bad.
 
Ok, I see the rubber pulley now! I'm guessing the clutch is the white thing right below it. Is there a good way to tell if my clutch is locked up? Do I just need to pull it all the way out of the deck to see how it spins? It would be cool if I could just replace the pulley without getting the clutch fixed too. I'll order the new belts and pulley right now. I do think the counter is totally shot, so I'll have to dig up a replacement. On the plus side, deoxit delivery date got bumped to today, so I'll be able to deox the switches and try for a signal later!
 
If you are having rewind problems like you stated it’s probably the clutch. He charges a very reasonable price to repair it so it may be best to have it done either way. Because it will fail if it hasn’t already.
 
Good news! Deoxing the two switches appears to have fixed the output. I have yet to check the line outs, but I expect those are also fixed. Will check tomorrow when I can drag the deck upstairs. In the meantime, I've ordered the new belts and rubber pulley, and I'm going to send the clutch out for repair ASAP. Once all of that is installed and working, I'll look into replacing the tape counter and recapping.
 
You are the first person I’ve seen willing to re cap one of these. keep us informed if there is any improvement in sound quality. I think you will need to create your own List of caps from looking at the parts on the board.
 
Huh, I wonder why that is. Wouldn't the same concern about electrolytics going bad apply here? I'll start making a list of caps today so they can hopefully arrive in a week or two. Bit of a general question since I'm new to this - is there anything I should watch for when choosing new caps other than capacitance (same rating) and voltage (same rating or higher)? I'm planning on using Nichicon KZ series electrolytics, and I'll try and choose film caps when I can find ones that have the right lead spacing and dimensions.
 
I think that for anything in the audio path you want to use ukl and wima films for anything under 4.7uf if they fit. Upw for non audio caps. The parts are pretty close together on the boards in these decks I don’t see a lot of film caps fitting.
 
Any reason you recommend UPWs? I did see those mentioned in a few places but there doesn't seem to be a consensus on what to use. I managed to pull out the rewind clutch (that e-clip was tough to pop!) and it's definitely binding. Hopefully a fixed clutch plus new belts and pulley will fix up the rewind. I do wonder if there's a way to replace the rubber on the clutch itself. Don't think Mark does that, but maybe it doesn't need it.
 
As far as the caps I’m going off of Marks recommendations in prior posts for receiver lists. I’ve done 4 receivers in this manner and results are fantastic. The UPW is what he specs for power supplies and non audio caps, For audio caps low leakage of the UKL. Panasonic films are preferred for the small values but mostly out of production and everyone is using wima for those.
 
voxswain said:
Good news! Deoxing the two switches appears to have fixed the output. I have yet to check the line outs, but I expect those are also fixed. Will check tomorrow when I can drag the deck upstairs. In the meantime, I've ordered the new belts and rubber pulley, and I'm going to send the clutch out for repair ASAP. Once all of that is installed and working, I'll look into replacing the tape counter and recapping.
Click to expand...

I just did my deck and the belt kit comes with the three belts and two idler tires. I also replaced the ff/rw pulley. I had my clutch repaired by MTF.

You may only need to clean the counter assembly by spraying some fader lube on the gears and counter.
My unit was still having trouble with ff/rw so I pulled the small belt, that resulted in perfect function. I think the replacement small belt is too tight causing the gears to bind, I reinstalled the old small belt and all was working. When the counter binds it causes the sensor to stop the function.
 
Unfortunately I don't have any FaderLube, but MTF has generously offered to fix my counter with the clutch, so I'm sending both out today. In the meantime, I've been working on building out a recap list. Here's my list so far for the Rec/PB amp:

Grimshot 2020-10-16 09-20-41.png

How's it look? (Note: this is only for the electrolytics, since I'm assuming the rest don't really need to be replaced.) The main thing I'm worried about is lead spacing, but I'm not really sure how to measure the spacing for each cap. Is it safe to assume that most or all of these will fit? I also need to check if the deck has any caps that are different from the schematic. Not sure how common that is compared to receivers and the like. Thanks for any feedback!
 
The 4.7uf wima are pretty big, I’ve run into them not fitting before. I would order some UKL for that spot too just in case they don’t fit. If those are all radial lead caps im sure the spacing is ok. The ones with the really close 2.0mm can still fit in the wider spots there is plenty of lead.
 
The UPW caps are fine for sound / signal path.

The UKL caps are for sensitive areas where low leakage REALLY contributes to keeping the noise floor low.
BUT this is usually in phono amps, although tape playback in the early stages can qualify.
I go by what THEY originally had in there - special low leakage from back then (NL) or capsistors (CSZA) or tantalums(CSSA).

Film is usually the best replacement IF IT FITS!!!

The straighter path an electron has between the foil face and the output connection of the cap - the better the sound (IMO).
Capacitor "rolls" just can't HELP being inductors.
Capacitors that have "schoopage" have that far straighter path.


As for the overall replacement of audio carrying caps in the cassette decks - well, the receivers heat up and dry out caps sooner and analog tape distortion levels make it harder to perceive improvements.
 
Thanks for the info, Mark. Here's my tentative CT-F9191 BOM:
recpb.png
dolby.png
control.png
switch.png
power.png
How's it look? Wasn't sure if you meant UPWs for only the signal path or for everything, so I've gone for everything here. If there's a series of caps that would be more suitable for the boards other than the playback and Dolby boards, please let me know and I'll swap them out. While I'm ordering parts, is there anything else that's worth swapping out? When I rebuilt my SX-636 it was recommended that I swap out some transistors that were likely to go bad, so I'm wondering if it's the same situation here. Excited to order these :biggrin:
 
If I am going to seriously evaluate the choices you made, I need more data from the BOM section of the service manual for each capacitor position.
As well as an identification of THAT position.
If I have to dig it out and look it up for each capacitor it will take me far too long.

also 23 of one type of cap won't cut it, there are 23 different positions that are different. perhaps there are several common descriptions in the BOM.

RWF-041 C101 10 25v cea 100p 25
RWF-041 C107 10 25v cea 100p 25
RWF-041 C108 10 25v RCH-022 // uh oh! !!!
RWF-041 C114 10 25v cea 100p 25
and then there's this:
RWF-041 C116 10 16v cea 100p 16
ok, I see that is 1 of 11...

you get the idea, i hope?
 
You must log in or register to reply here.
Back
Top Bottom