Sanyo VHR-D4710G VCR no sound.

[hugocarmo]

Hi again guys.
Today I have a problem with this Sanyo VCR.
I bought it online, It worked sometimes.
I recap the Power supply and it started working fine.
Image is perfect and all digital effects too.
All of a sudden it stopped outputting sound. I checked for dried solders an all boards and soldered when needed, no fix.
I have no sound on playback, on tuner, or aux in.
On symptom I noticed is when it was working fine, the HI-FI led was on when I power up the VCR, now is OFF, A-B leds are on but when I put a tape they go off.
On one of the sound processing boards (has two) there´s a relay, I remember that when it was fine, when I power the vcr on, I hear the relay switching but now it doesn´t.
I´m struggling to find what is causing the problem. If it´s an IC, I think It´s garbade dispite the image still great.
I bought the service manual, wich I attach in my post.
I hope once again someone can help me fixing this VCR.

Service manual
https://drive.google.com/file/d/1TRE...usp=drive_link

Thank You all.

Hugo do Carmo.

[redk9258]

Maybe clogged heads? Maybe a tracking issue? Try different tapes. Try a recording made on this VCR. Don't scrap it. You can still use the linear track like a non HiFi VCR!

[hugocarmo]

Originally Posted by redk9258

Maybe clogged heads? Maybe a tracking issue? Try different tapes. Try a recording made on this VCR. Don't scrap it. You can still use the linear track like a non HiFi VCR!

Hi again redk9258.
I don´t think tha problem is on the heads, because I have no sound even on aux in, or tv channels.
And forgot to mention on the first post that the vu meter leds were working before and now they´re off too.
I tried lots of differente tapes and the same result...

Thank You.

[Electronic M]

Maybe the relay failed...

[hugocarmo]

Originally Posted by Electronic M

Maybe the relay failed...

Thank You for your answer.
Is there any way of testing the relay?

Thank You.

[Alex KL-1]

For a given generic relay, a example:...

Is needed to locate the C (common), NC (normally close) and NO (normally open) contacts. Some are described on the body of relay, sometimes below (then is needed to remove to check it). Sometimes not have any markings, but for sure, some contact is NC when the relay have 3 pins for each contact. Some relays have only 2 pins for contacts, and have only NO or NC contacts.

2 pins absolutely are for the coil. For example, is possible to drive it (with relay removed from PCB) with a 9V battery if is a 9 to 12V relay, for testing, and watching if the contacts switch between NC and NO. Open coil, of course, render it useless.

Then, a generic 2 contact relay with NO and NC contacts (an example for "stereo" audio commutation in equipment) will have 8 pins at least: 3 for one set contact (the C, NC and NO), 3 for another, and 2 for the coil.

[Alex KL-1]

Originally Posted by Alex KL-1

For a given generic relay, a example:...

Is needed to locate the C (common), NC (normally close) and NO (normally open) contacts. Some are described on the body of relay, sometimes below (then is needed to remove to check it). Sometimes not have any markings, but for sure, some contact is NC when the relay have 3 pins for each contact. Some relays have only 2 pins for contacts, and have only NO or NC contacts.

2 pins absolutely are for the coil. For example, is possible to drive it (with relay removed from PCB) with a 9V battery if is a 9 to 12V relay, for testing, and watching if the contacts switch between NC and NO. Open coil, of course, render it useless.

Then, a generic 2 contact relay with NO and NC contacts (an example for "stereo" audio commutation in equipment) will have 8 pins at least: 3 for one set contact (the C, NC and NO), 3 for another, and 2 for the coil.

Generally , the contact pins are grouped together, at opposed side of the coil contacts.

[hugocarmo]

Originally Posted by Alex KL-1

Generally , the contact pins are grouped together, at opposed side of the coil contacts.

Thank You Alex.
I´ll see what can I do!

[Electronic M]

Originally Posted by Alex KL-1

For a given generic relay, a example:...

Is needed to locate the C (common), NC (normally close) and NO (normally open) contacts. Some are described on the body of relay, sometimes below (then is needed to remove to check it). Sometimes not have any markings, but for sure, some contact is NC when the relay have 3 pins for each contact. Some relays have only 2 pins for contacts, and have only NO or NC contacts.

2 pins absolutely are for the coil. For example, is possible to drive it (with relay removed from PCB) with a 9V battery if is a 9 to 12V relay, for testing, and watching if the contacts switch between NC and NO. Open coil, of course, render it useless.

Then, a generic 2 contact relay with NO and NC contacts (an example for "stereo" audio commutation in equipment) will have 8 pins at least: 3 for one set contact (the C, NC and NO), 3 for another, and 2 for the coil.

Sounds like you're assuming SPST and SPDT relays....If it's for switching between linear stereo and HiFi stereo DPDT contacts are more likely... Double throw relays test the same as single pole only you have 2 separate sets of contact terminals to check.

[hugocarmo]

Hi all.
I took pictures of the boards and the relay.
I´ll post it here.

Both boards: https://pasteboard.co/j0N6nuhtwaBx.jpg

Relay: https://pasteboard.co/7TO64xV3XflY.jpg

Relay Solder side: https://pasteboard.co/aDpGgwg0IPUH.jpg

Thank You all once again!!

[redk9258]

You didn't put a cap in backwards in the power supply, did you? Seems like a power issue to the audio section.

In your service manual, it looks like there are 2 audio PCBs. I would check those carefully for voltage and connections.

[hugocarmo]

Originally Posted by redk9258

You didn't put a cap in backwards in the power supply, did you? Seems like a power issue to the audio section.

In your service manual, it looks like there are 2 audio PCBs. I would check those carefully for voltage and connections.

I redk9258.
I don´t think so, because after the psu recap it was working well.

Thank You.

[jr_tech]

Originally Posted by hugocarmo

I don´t think so, because after the psu recap it was working well.

For how long?... I have observed backwards installed caps working ok for several hours before failing (usually shorting).

jr

[hugocarmo]

Originally Posted by jr_tech

For how long?... I have observed backwards installed caps working ok for several hours before failing (usually shorting).

jr

It worked for a day or some more.
I´ll double check but I don´t think that´t the issue.

Thank You jr_tech.

[hugocarmo]

Originally Posted by jr_tech

For how long?... I have observed backwards installed caps working ok for several hours before failing (usually shorting).

jr

Just checked the caps, all soldered in right polarity.