Restoring old Cassette tape recorder

MrUserNameIV

MrUserNameIV

SenselessActsOfCreation
I was doing some thrift shopping today, and came across an old JVC cassette recorder (JVC CD-1770) for $10 so I figured I'd bring it home and see about sending some tracks out my daw into it to play with smashing the snot out of the tape and circuitry for a low-fi-ish effect. When I hit record and play, it appears to be previewing what it's recording and it sounds really cool, noisy, saturated (actually a bit wider of a stereo image than my DAW which is interesting). Something that would be fun to send a drum bus to and blend for effect, or sample a kick drum through with it pinned.

First off the bat, I'm noticing a few problems that are preventing me from having my low-fi fun.

First problem is that the play, record, rewind and ffwd buttons randomly pop up. Sometimes they stay down for a bit, but sometimes I can't get them to stay down and they disengage the recording function. Could this be a part that just needs a bit of lubrication that might be catching and making it think it's at the end of the tape? Once in a while rewinding and fast forwarding makes it less of an issue.

Second problem is when playing back something that is recorded. I played back a pre-recorded cassette tape I had sitting in a closet and it sounds perfect (play head appears to be doing well), but after I record something out of my daw into the unit to a tape, I play it back and it sounds a bit like a blown speaker/bad cable/blown circuitry. It leaves a ghost recording of anything previously recorded on the tape that's almost as loud as the signal itself. I'd imagine the record head hasn't been cleaned in a few decades. Could this be the culprit (a good cleaning and demagnetization) or is some of the record head circuitry likely fubared?

Any recommendations?
 
Cleaning both the erase and rec/play heads are always a good idea. (Isopropyl alcohol and q-tips.)

But more then likely, it's something electrical in nature and explains why it was only 10 bucks.

About the transport keys popping up, there's probably an auto stop sensor that's set too sensitive or there is other mechanical issues that are causing too much friction on the drive and it it thinks its at the end of the tape.

Best bet is to hunt down a better deck that can be demonstrated to be functional before you pay for it.

Cheers! :)
 
The Ghost of FM said:
Cleaning both the erase and rec/play heads are always a good idea. (Isopropyl alcohol and q-tips.)

But more then likely, it's something electrical in nature and explains why it was only 10 bucks.

About the transport keys popping up, there's probably an auto stop sensor that's set too sensitive or there is other mechanical issues that are causing too much friction on the drive and it it thinks its at the end of the tape.

Best bet is to hunt down a better deck that can be demonstrated to be functional before you pay for it.

Cheers! :)
Click to expand...

Maybe if I find a schematic I can hunt down the culprit. It does need to be opened up and cleaned inside, so that could also be contributing. A few of the buttons were really noisy and seemed to have a loose connection.

I figured it was only $10, so it's not too big of a deal.
 
MrUserNameIV said:
Maybe if I find a schematic I can hunt down the culprit. It does need to be opened up and cleaned inside, so that could also be contributing. A few of the buttons were really noisy and seemed to have a loose connection.

I figured it was only $10, so it's not too big of a deal.
Click to expand...

True. It wasn't a major investment! :)

Piano key transports are generally considered to be the lowest form of quality on the design scale and JVC had mixed reviews back in the day as to their over all quality. So you might well find lots of plastic parts inside where better decks used metal ones which would stand up to more wear over the years. Though your model appears to be a decently made model, so it might be just a case of giving it a good cleaning if there is a lot of gunk in there from exposure to dust, smoke and household cooking grease, etc.

I've also seen instances where the heads are so clogged with oxide build up on them that they can't erase or record properly, so there too, giving them a vigorous cleaning first before you start looking for electrical issues is also a good idea.

Cheers! :)
 
I'm cleaning the heads and various rollers with some rubbing alcohol and q-tips. It looks like one of the pinch rollers is a little bit stiff (maybe the culprit for it stopping all the time?) Would it harm things to spray a little bit of WD-40 in there to lubricate things after cleaning it or would that ruin the heads? The heads have a little bit of noticeable dark brown and black gunk coming off on the Q tips (not a ton but the heads look really shiny and new now). I suppose I'll have to let it dry for a while before I see if the cleaning worked. I also cleaned up the tape chamber in general as it was dusty as hell in there.
 
I wouldn't use WD-40. Don't use it. Clean the heads until no more residue comes off. Most of these old cassette decks, unfortunately, have lots of rubber parts (belts, idlers and pinch rollers) which need attention after many years (usually replacement for belts / idlers and sometimes just reconditioning of pinch rollers - no definitive rule on that). What I'm saying is that your recorder most likely has numerous problems which need to be tended to by someone who has the experience with those kinds of things. This most likely isn't a quick fix. But if you wish to proceed, start by cleaning the heads properly. Do the same on the pinch roller but the alcohol will dry it out (tape slips) so you'll want to use some rubber conditioner. The next thing is to carefully dis-assemble the recorder (take photos and notes to put it back together later) and look at ALL the rubber parts inside, examine them. It'd be best to replace all of these (and cleaning the areas of the old rubber residue). The process will give you the best education on how to service those units. It's at least a good start. This might not be difficult to do but it's an involved, potentially lengthy process, to do it right. I've done several cassette and VCR decks, reel to reels, over the years. It's usually mechanical stuff that's the problem on those types of units. The studying others doing it, being curious, having the tools, patience and actually doing it is the experience you'll need.
 
Cool, thanks for the advice. Good thing I didn't spray WD-40. I kind of half expected it might screw the heads up, but I thought I'd ask. This unit was fairly cheap ($10 at Goodwill), so I'm not expecting too much (If I can get it to record to tape and quit stopping all the time it'll serve the function I'm hoping to use it for as signal passing through it or playing back tape sounds pretty cool). If It's something I can fix for not too much money, it would be fun to do. I've had interest in playing with old electronics and possibly starting to circuit bend stuff, so I figure it's a good start to learn how to pull some old thrift store electronics apart and see if I can make them work for me. I've thought about trying to pull apart old tube radios and passing signal through them as an effect box, but that's down the road for me if I can learn how to do that stuff well. I'll see how the cleaning effects it. I half expect that it might improve the record/erase (fingers crossed) but probably not the tape stopping.
 
Update: The cleaning didn't fix the issue with the record/erase head. So then, I gather, it must be a problem internally with the electronics. Next step is to open it up and see if anything needs cleaning inside. Any suggestions?
 
If you can spot any plug-able/un-plug-able wiring harnesses that connect one board to another that are are part of the audio chain, try re-seating them and/or cleaning the electrical contacts on them if they look corroded or oxidized in any way.

Cheers! :)
 
++to what Jeff said. I actually had to re-read the original post and Jeff's original reply was right on that it looks like an electronic issue (rec issue sounding like bad circuitry) and that "explains why it was only 10 bucks..... Best bet is to hunt down a better deck that can be demonstrated to be functional before you pay for it." Yeah definitely re-seat connectors / clean from possible oxidation or better yet get a better, functional deck, as Jeff said.

There was something else that MrUserNameIV quoted:

MrUserNameIV said:
Something that would be fun to send a drum bus to and blend for effect, or sample a kick drum through with it pinned.
Click to expand...

Remember that this is likely a 2 head deck only (1 playback/rec head and 1 erase). You won't be able to use it in an effects loop or blend the tape saturation with the original sound. You need a 3 head deck for that and even then it will be very slightly delayed, the signal coming off tape (you need to have off tape monitoring) but it would be better than what you have now and the slight delay could be a cool effect too. Now unless I misunderstood what you're trying to accomplish?
 
Oh, I don't need more than that for the purpose I'm wanting to use it. Mostly, just going to send out of the DAW (stereo or mono, depending on what I'm sending) into the tape deck, record what I want soloed/bussed, and then record that back into the DAW to blend digitally. If I need to adjust I can record it with several different settings and see what sounds the best when I fly it back into my DAW. I've got Apogee I/O so I'm not too worried about the digital end. If I were to go analog for mixing, I'd probably go with a multitrack reel to reel rig (one of these days).

I'll open it up and see what I can find. It may end up just being a $10 paperweight, but I figured it was worth a try.
 
Oh, OK, I see.... Yeah, open it up and see what you can do, definitely.... A few questions: Are you connecting the recorder from your computer to the RCA LINE IN? When recording, are the VU meters needles way into the red pinned or are they of more moderate levels, around 0db? When you playback the recorded signal, does it also distort while directly listening back via it's headphone output? How about RCA's out? Is the previous signal now erased when you cleaned all the heads, including the erase head?

If you have some time, read the following repair article on cassette decks / tape decks:
Sci.Electronics.Repair FAQ: Notes on the Troubleshooting and Repair of Audio Equipment and Other Miscellaneous Stuff

In the article, section 4.12 (about distorted recording), here's what it says:

First determine if it is a record or playback problem - play a tape
recorded on another machine or a commercial prerecorded tape.
Try a tape from this machine on another known working tape player.

If record is the problem and it has very distorted sound, this may be
a sign of a bad bias oscillator or switching circuit or record switch.
The bias is an ultrasonic signal that is impressed on the tape along
with the input signal. Without it, the sound will be highly distorted.
In effect, it is a linearizing signal.

Check that the record select switch is clean - it may have many contacts
and may have collected a lot of crud. If behavior changes with each
activation of the record switch, get some contact or tuner cleaner spray
and use the extension tube to spray inside the switch (with the power
off), put the switch through its paces several times and allow to dry
before powering it up.

If it is a portable subject to abuse, check for bad connections as well,
especially if, say, one channel comes and goes.

Beyond this, you can try to measure the signal going to the record heads
while in record mode. You should be able to see a high frequency signal
in addition to the input signal. If the either of these is absent, then
you need to trace back to its source and at this point will probably need
a schematic.
Click to expand...

In section 4.13, (about previous recording not being erased), it says:

In this case both the original and new audio appear on the tape. The most
likely cause (assuming your deck doesn't have some fancy sound-with-sound
or sound-on-sound modes that may be engaged) is a faulty erase head or its
driving signal.

The erase head precedes the record head and probably uses the same high
frequency signal as that for record bias to totally wipe the previous
recording. (However, on really really cheap tape recorders, erase may just be
performed by a permanent magnet.) If the new recordings are really distorted,
the bias oscillator itself may not be working. The erase head is either part
of the REC/PLAY head assembly or a totally separate head. Check for broken
wires to this head as well. If you have an oscilloscope, monitor the signal
during record. The erase head could also be defective or really dirty.
Click to expand...
 
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