Early 1980s Hitachi VCR Having Video Problems
 

Hello Everyone, about a month and a half ago I had found at a local computer store's freebie pile an early 1980s Hitachi VT-8500A Top-Loader VCR that was in need of a little TLC (it needed a complete set of belts because it wouldn't rewind, fast forward or play) and I just got it in complete running order yesterday afternoon, the only issue is that its not putting out any video when the tape plays just a blank, black screen and that's it, and I'm not sure why its doing that. Its just so frustrating because I'm just so close to getting it running fully and the only thing keeping it from being a fully functioning VCR again is the lack of video playback currently.

Any ideas as to where I should start troubleshooting the no video playback issue?

Do you have audio? If you feed it an RF video signal with actual program material will it pass that to the outputs?

I ask because you mentioned in your old thread that you were testing with a flatpannel set and no signal to the VCR tuner....Some flat panels are finicky and won't show a picture unless the signal they get is near perfect.

If audio and video are dead even thru the tuner you will need to get a service manual and a oscilloscope to troubleshoot it....Or get an ESR meter and some new caps and HOPE it is a bad cap and that you manage to find and replace it.

If only the tape video is dead the tape heads are either dirty or bad, or the signal chain has a problem.

I double checked it with an older CRT Television and it seems that the Tuner is working fine its just the VCR Part when playing a tape doesn't work right, all I get is a a blank black screen, and no audio either. So I'm not sure what's going on with it, the VCR Doesn't put out any video or audio when playing a tape in either the RF (channel 3 or 4) or the A/V outputs so somethings wonky about the video and audio signal going from the video and audio heads of the VCR to the output signal area.

Could be some old dried out electrolytic in the E-E V-V switching or muting since it's effecting both audio and video, that's when it switches from tuner source to video tape playback.

Where would that circuit be in the VCR? Because I was definitely thinking the same thing but I'm not sure where I would find that circuit in this VCR, that's when a service manual would come in handy...

You need a service manual to track that down, unless you have a ESR meter and happen find a bad capacitor by checking all on the board.

Well That's going to be kind of tricky because from what some of the people on here were telling me, the service manual for the Hitachi VT-8500A was only available as a seminar handout and I wasn't alive in the early 1980s to be able to of acquired one, and I have no idea if sam's ever covered this VCR or not in their photofacts, and even if they did I can't afford to spend $25 on their website to buy the manual.

Don't now about that Hitachi thing we had the VT-8500A manuals I used many times since I was the one there that worked on the things and it was a popular model. There might have been a training manual that was passed out at training seminars. That was pretty common. We were an authorized Hitachi servicer, had a subscription to the printed manuals as long as they were available in printed form.

Anyway you might search ebay and then save the search, set it to email you if one ever shows up.

Meanwhile I will look in my old pile of manuals next time I drag all that stuff out to see if that one escaped the dumpster...


http://www.videokarma.org/attachment...2&d=1332548521

http://www.videokarma.org/attachment...1&d=1332542288

Alright thanks, I really apreciate the info and I apreciate you searching for that manual for me in your stash. like I said I would really love to get this VCR going because it would be the oldest VCR I ever owned that was able to be restored to fully funtioning by myself. I actually had a late 1970s Panasonic toploader with the knob style tuner on it that someone at church gave me about a decade ago that had an issue with it only playing back videos in monochrome instead of color like it was supposed to and I wasn't sure how to fix that issue back then although I'm guessing it was probably something as simple as a bad electrolytic cap in the chroma board somewhere thinking back on it now, but like I said back then I didn't know about that kind of stuff and my mom didn't want me keeping that VCR around the house because I already had a lot of stuff laying around in my room that they were kind of wanting me to get it going and sell it or scrap it out because my room was becoming a fire hazard supposedly according to my mom.

I wish you luck buddy!!!

Dont give up whatever ya do!!!! :) (Try not to)

I'm trying not to but this VCR is kind of got me stumped at the moment its strange, if it isn't one thing its another thing going wrong with it, first it was the belts and now its video and audio problems... :sigh: I wish I could locate a service manual for this thing but I have yet to find one for it. :no:

OK So a little update on this VCR, I think I found the culprit that's causing the no video and audio issue for the VCR when the play button is pushed, I found a 470 MFD 10 Volt electrolytic capacitor in the bottom circuit board near the back of the circuit board that was bulging like crazy, whereas the rest of the electrolytic capacitors in the unit were just fine, its a Nichicon capacitor and I have a picture of the capacitor below. The only problem was that the circuit its in doesn't seem to be labeled as a mute circuit from what I can see but I'm guessing that's the circuit you were talking about where this capacitor is in.

EDIT: Figured out that the "bulge" on that cap was actually just an epoxy coating of some sort. Took everything apart again that I had unhooked before, and rehooked it up again and now I have video and audio now, but now I have a new problem yet again, it seems that the VCR is playing the tape too fast and I have no idea why it would be doing that. So any assistance with this issue would be helpful. This VCR is 95% running, just that last 5% is what's keeping it from being 100% (which is the issue that I'm having right now of it running too fast.)

As mentioned in the other topic, you probably are not getting the control-head pulses into the rest of the VCR, either from a dirty head or maybe the head or its wiring are bad.

Well I've tried to clean the head a couple of times and it seems like its fairly clean (no black residue comes off of it.) And if the tape heads were bad, how hard would it be to get a replacement head for it?

How is the capstan/pinch roller? If it ain't gripping the tape and controlling it's speed then the take up reel may be what is moving the tape (something that should not be allowed to happen).

Well I was watching the the capstan and Pincher roller assembly and even tried to see if I could push my finger up against it to see if I could get it to go up against each other more and it seems its gripping properly, I even tried recording a test tape and it didn't seem to make much of a difference whether or not I had switched the speed switch on the fly while it recorded or not it just recorded and played back at the same speed (which was a really fast speed.) Also it seems that the tuner that's built into the VCR isn't working right as I'm not getting any sort of white noise out of it and I can't get it to tune in my converter box for a signal source, it works by letting the converter box signal pass through to the TV itself but it won't go through the VCR's tuner, all I get is a blank black screen (just like I did with the VCR when I tried playing tapes in it before I got that part fixed.)

No audio and video is weird, these machines weren't advanced enough to black out the screen and mute the audio if there was no video signal, so you should at least get audio and a garbled picture.

Well I finally got the tuner working again but of course there's no audio, just video. And I've done some more checking into the capstan and pincher assembly, and I noticed a "track" worn into the pincher roller and also that the pincher roller was pretty hard so I tried using some rubber renue on it to see if it would help the roller grip better and it definitely softened up the rubber on the roller, but its still playing too fast, no amount of cleaning the heads or anything is fixing it. So I'm guessing that the heads might be bad...:sigh:

Also when I was taking the tape cover off (the part you insert the tape in) I accidentally dropped a screw down into the VCR and I was trying to get the screw out and in the process screwed up the clock display (I accidentally forgot to unplug the unit when I went to retrieve the screw.) So what would of the screw hit that would of messed up the clock display? Also I think that the same incident that screwed up the clock display may have been what brought the tuner back to life minus the audio portion of it.

You probably shorted something out with that screw.

The speed is regulated by the capstan and a complex electromechanical feedback loop that takes in speed sensor, tape signals (control track, etc.), etc. and adjusts motor speeds etc. accordingly. Several different things could be bad, but it's looking like most remaining possibilities are electronic....Those circuits require quite a bit of VCR specific knowledge and test equipment to properly troubleshoot and adjust...Enough so that it may be better to just find another VCR....

I see, well would you be interested in it, and monkeying around with it or know anyone on here that would be interested in it? I would hate to see this thing get recycled, because its a complete unit with its original remote and owners manual and everything.

Before worrying about replacement heads, you should do tests to see if any are even needed. Put an oscilloscope on the output of the control head to see if it is making a signal when a tape is playing. (If you do not have a scope yet, you should get one; many used ones are cheap and not too hard to learn to use.)

Regarding the speed and test-tape issues, the key is to compare using a known-good VCR. For example, if you play a tape recorded on the Hitachi on another machine, does it play properly? (And, switching the speed while a VCR is recording may not even work; you might have to hit Stop first. But, trying each speed available is a good plan.) Make sure your test VCR can play all the speeds of the Hitachi (so, don't use a VBT-200 or VCT-series machine to try to play an "SLP" or "EP" recording).

No I don't have a 'scope and I have said this several times before on here, I can't afford to get one because all of the 'scopes I've seen for sale on ebay are going for well over $100 and I don't have that kind of money laying around.
As for the test tape I couldn't even make a proper test tape because the tuner on the VCR isn't even working right so I had no way to get a test signal into the VCR for recording test purposes.

OK. If the VCR has video/audio input and output jacks, you could try connecting a digital-TV converter box. For oscilloscopes, look for hamfests in your area maybe, when you can afford one.

About 5 years ago I got my first working scope at a radio swap meet for $50 (and a later got another for cheaper). Look locally. Check craigslist, swap meets/hamfests, and schools and colleges surplus equipment sales, etc....Odds are you can find a decent one cheaper than I did.

The key to getting good tools is to, know what you want, and always be on the lookout for it....Just because it's too expensive one place and time does not mean it wont be cheaper elsewhere later.

I have looked locally and most of the schools got rid of any equipment like that years ago, and I don't have any swapmeets near me that I could go to, I live smack dab in the middle of northern Indiana which has nothing in the way of ham-fests or swapmeets for radios and TVs, and the local flea markets and antique stores have yet to have anything like that for sale in them, the closest I've seen to test equipment like what you are talking about was a signal generator at a local flea market, and it was in my price range but I didn't have the money on me at the time to buy it and when I went back the next time when I did have the money for it, it was already gone. So basically where I live it isn't much of a hotbed for vintage test equipment.

I don't think there are any hamfests or radio swap meets in my area, the closest ones that I know of from reading through people's posts on here in VK is in Chicago or near Detroit and I'm not too thrilled about driving to either location by myself because of traffic and because I'm just not familiar enough with those areas to drive in them on my own.

Well, there is one in La Porte on February 27th. Maybe you will be lucky if you go there.

http://www.lpcarc.org/

http://www.arrl.org/hamfests/search

OK. Well that's still about an hour away but I'll see if I can make it over there.

OK So here's something interesting that this VCR is doing now, I went to plug in the VCR and try it out again just to see what it was doing and sure enough the tape was playing and detecting the proper speed now all of the sudden, but here's the catch its gone back to not putting out any audio or video again, but this time instead of the no audio and video signal issue being just in the VCR part, its also in the tuner part now as well, all I get is a blank black screen, just like before, so here's where the interesting part comes in, it seems that when the VCR is putting out the audio and video signal like its supposed to is when the VCR doesn't play and detect the proper playback speed of the tape, but when the VCR isn't putting out any audio or video signals it detects and plays the tapes at the proper speed...:scratch2:

Any ideas as to what would be causing this rather mind boggling issue?

UPDATE: I just figured out what this VCRs problem is I took the bottom cover off so I could get a look at the bottom circuit board to see if I could find what part was shorted to cause the clock display to malfunction and sure enough I found that C549 had a cold solder joint on the positive lead and a lifted trace and no solder attaching the negative lead to the board, and I did notice that it was a newer capacitor replacement as it doesn't match design wise or brand name wise to the rest of the electrolytic caps on the board. So how would I go about repairing this issue?