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Old 18th Oct 2017, 11:40 pm   #1
dj_fivos_sak
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Default Sanyo VTC 9455 Betamax - No colour

So, I just found this super rare VTC 9455 multi system VCR. The problem is there's no colour in all modes (Playback and both E-E modes, RF and line inputs). The tuner's AUTO-PAL-SECAM switch does absolutely nothing and the corresponding LED indicators on the front panel don't light up. Since there's no way finding the service manual for this model, does anybody know where to start? Bad caps? Power supply or chroma board? Any info appriciated.
BTW, The mechanism is the same as the VTC 5500 and 5600 European/UK models except that this one has an electronic eject button.

Fivos
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Old 19th Oct 2017, 8:39 am   #2
Nickthedentist
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Default Re: Sanyo VTC 9455 Betamax - No colour

Quote:
Originally Posted by dj_fivos_sak View Post
The tuner's AUTO-PAL-SECAM switch does absolutely nothing and the corresponding LED indicators on the front panel don't light up.
I think I would start right there, i.e. trace how the LEDs are meant to be energised depending on the switch position. It sounds very like the switch isn't making contact properly, or that a supply voltage is missing.
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Old 19th Oct 2017, 1:13 pm   #3
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Default Re: Sanyo VTC 9455 Betamax - No colour

Thanks for your answer. But I think the LED's have nothing to do with the colour circuit. Would a photo of the bottom circuit boards give you a clue of which one is the chroma board?
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Old 19th Oct 2017, 2:25 pm   #4
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Default Re: Sanyo VTC 9455 Betamax - No colour

I would have thought the chroma board would have printing on saying things that would identify it. If it has not then look for the Silver can Quartz Crystal box.
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Old 19th Oct 2017, 4:57 pm   #5
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Default Re: Sanyo VTC 9455 Betamax - No colour

Here's a couple of pics from the bottom PCBs. I guess you are talking about that silver box?
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Old 19th Oct 2017, 6:46 pm   #6
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Default Re: Sanyo VTC 9455 Betamax - No colour

Hi,
I would assume ( a dangerous thing ! ) that there might be different crystals for the different Tv standards. these frequencies should be able to be found out, and then there could be some crystals ( small metal cases ) with the frequency on them.
It might be worth noting the part numbers on the ic's and see if doing a search on them gives any info on their function.
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Old 19th Oct 2017, 7:28 pm   #7
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Default Re: Sanyo VTC 9455 Betamax - No colour

I agree with Nick, look for the obvious and should the led's not be lit, ask why not? Could the lack of illumination be down to a faulty 5 volt ic regulator supply line also used in the chrominance circuit for example.

The answer may or not be the reason for no colour but to dismiss his advise out of hand when you do not have a schematic could well leave you chasing dead ends.

Chris
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Old 19th Oct 2017, 7:32 pm   #8
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Default Re: Sanyo VTC 9455 Betamax - No colour

Second photo about the middle of the right side board next to an in line IC that has odd bulges on it, is the crystal I am talking about. As Peter B says check the IC's and white lettering in that area.
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Old 19th Oct 2017, 7:57 pm   #9
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Default Re: Sanyo VTC 9455 Betamax - No colour

Hi.

I would also agree with Nick in that it's likely a supply line is missing. The fact that none of the LEDs are lighting seems to reinforce this point.

I remember having a similar no chroma problem many years ago in a Sharp VC7750 early VHS set. The loss of supply turned out to be due to a s/c electrolytic. This is something worth bearing in mind where long dormant equipment is brought back into service. Some electrolytics take objection to the sudden stress if not gently reformed.
For long dormant VCRs, and after a visual inspection, I usually connect the VCR to mains for a few seconds then disconnect. I repeat this several times in the hope it will help to reform most of the electrolytic capacitors. I've so far not had any problems with this approach.

Regards
Symon.

Last edited by Philips210; 19th Oct 2017 at 8:04 pm. Reason: text edit
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Old 19th Oct 2017, 10:33 pm   #10
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Default Re: Sanyo VTC 9455 Betamax - No colour

Thank you all for your suggestions. This model is a bit strange. I think it has the power supply split into two modules. I believe the one PCB in the metal shielding is the primary supply and the other PCB next to it is the secondary one. And I noticed it's a 110-240V machine with no selectable voltage. Does this mean it uses a switching power supply? And what are these pots that I have circled? My VTC 9350's power board has a pot for 12V adjustement. So is this case the same here?

Fivos
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Old 19th Oct 2017, 10:51 pm   #11
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Default Re: Sanyo VTC 9455 Betamax - No colour

Don't know what the pots are for. But do NOT adjust them or anything you don't know what is for.
Make sure all the plugs are properly seated. Those on the bottom PCBs aren't at the moment.
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Old 19th Oct 2017, 11:10 pm   #12
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Default Re: Sanyo VTC 9455 Betamax - No colour

I won't adjust anything until I recap the whole thing. The moment the photo was taken I had dissasembled the unit. That's why the connectors aren't seated properly.
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Old 20th Oct 2017, 9:21 am   #13
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Default Re: Sanyo VTC 9455 Betamax - No colour

Hi,
I think a recap would probably be a good idea. But please be careful on the switch mode supply side of things, the high voltages can bite !
it is possible that this model uses a switch mode supply to convert the mains voltage down to a couple of dc supplies, which may then be further regulated by the second board.
quite a challenge, but definitely worth it ...
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Old 20th Oct 2017, 9:56 am   #14
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Default Re: Sanyo VTC 9455 Betamax - No colour

BTW, I love the bizarre styling of this machine. The top section looks identical to the machines we would have had here in Europe, the woodgrain lower panel looks like something slapped on for the American market, and the baroque-styled escutcheon looks like it's been robbed off a French 1950s radio. And the ALL SYSTEM ----- SOFT TOUCH. (complete with full-stop) might as well be a DIY label-maker job.
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Old 20th Oct 2017, 12:21 pm   #15
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Default Re: Sanyo VTC 9455 Betamax - No colour

It is actually a Middle East model but also used to be sold in Greece back in 1981-82. All Sanyo TV and VCR sets for that market had golden/woodgrain covers/panels and that escutcheon on the front. My VTC 9350 says "IC electronics" on the logo lol ! Here's some close-up pics of the front of that beautiful machine. Too bad it's missing the clock/timer flap door. Good luck finding one of these...
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Old 20th Oct 2017, 1:48 pm   #16
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Default Re: Sanyo VTC 9455 Betamax - No colour

IIRC Greece used the same version of SECAM as the Middle Eastern countries, rather than the French & Eastern European versions.
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Old 20th Oct 2017, 2:22 pm   #17
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Default Re: Sanyo VTC 9455 Betamax - No colour

That's true. SECAM B/G to be exact. Sometimes called MESECAM as a recording system.
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Old 20th Oct 2017, 7:09 pm   #18
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Default Re: Sanyo VTC 9455 Betamax - No colour

Quote:
Originally Posted by dragonser View Post
I think a recap would probably be a good idea.
Thank you. I'll definitely recap at least the second board. I have one more question though. As soon as I hit the power off/standby button, I can barely hear a short hissing sound coming from the power supply. Does that mean bad caps? It's a switching PSU for sure…

Fivos
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Old 22nd Oct 2017, 10:32 am   #19
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Default Re: Sanyo VTC 9455 Betamax - No colour

Do you have a scope? Beware of jumping in just changing caps as you may break more that you fix. The only cps to be wary of are the low voltage ones on the primary side of switch mode power supplies! If you have a scope, turn the machine on then scope each rail to see the d.c. value is correct and see if there is any noise or hum on the rails, if they are clean, leave alone and look elsewhere! DO NOT ADJUST ANY POTS!! as said before. Man made faults are the worst and time consuming.
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Old 23rd Oct 2017, 10:58 am   #20
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Default Re: Sanyo VTC 9455 Betamax - No colour

Update: I managed to find an NTSC tape. I tried to play it and surprisingly, it seems I was wrong in post #1. The system selector switch is actually working. If set it to AUTO, it plays the NTSC tape in correct speed (BII tape) but still in black and white. If I set it to PAL or SECAM, the tape plays slow, as expected. So, the switch is working but maybe a voltage in the chroma circuit is missing.
Also, which lubricant do you recommend to fix the sluggish loading mechanism? I have to turn the loading ring by hand in order to unthread the tape...

Fivos

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