Just picked up a Panasonic PV-1730 Hi-Fi VCR - Page 5 - Videokarma.org TV - Video

Ed in Tx · #61 05-25-2022, 08:24 PM

Never mind...! I am done.

BTW.. If you still have the HR-S8000 I would advise unplugging it when not in use or it might burn your house down! No thermal protection and fuses wouldn't blow either. ☺

vortalexfan · #62 05-25-2022, 09:49 PM

Quote:

Originally Posted by Ed in Tx

Never mind...! I am done.

BTW.. If you still have the HR-S8000 I would advise unplugging it when not in use or it might burn your house down! No thermal protection and fuses wouldn't blow either. ☺

Nope, fortunately I don't have either of them anymore as they both suffered the burned up power supply issue you mentioned, although at the time I didn't realize that's what happened with them...

I'm sorry I didn't mean to confuse you with the descriptions of the VCRs I had. I was just describing what I thought they looked like.

vortalexfan · #63 05-26-2022, 02:57 PM

I got my new (to me) analog ESR Meter today, installed some batteries and found some test leads for it (I had some spare test leads for it from an old $10 Harbor Freight DMM that died on me a couple of years ago) that worked with it perfectly and I tested those capacitors I mentioned that we figured out were part of the take-up and supply reel motor B+ lines and they all tested bad (they pegged out the ESR meter, at least I think so anyways if I'm reading it right, in reference to an ESR chart I downloaded from the internet.)

vortalexfan · #64 05-26-2022, 04:02 PM

Alright so I actually figured out that if the meter pegs out the capacitors are good. So I figured out that C6-C8 were the actual culprits, they actually suffered from the notorious Matshuista(sp?) green corosion/leakage issue and that's actually the first time I've ran into that so far.

But I know Shango and J. P. Dylan have both discussed it in their videos quite often so that's the only reason why I recognized it once I found them with my ESR Meter.

Now to gets some replacement capacitors and install them and put the VCR back together and I think I should finally have a functioning VCR again.

vortalexfan · #65 05-26-2022, 06:14 PM

Well another update on the VCR, I did manage to find some capacitors for the VCR in my capacitor stash, and installed them, and put the VCR back together and it is partially fixed, the VCR is now powering on all by itself now when you plug it into the wall, and the take-up reel spindle is now spinning at a much faster speed than it used to when it is doing the self-diagnostic check.

But its still not spinning up the supply reel spindle and the video head drum isn't spinning up either in the self-diagnostic check, so I wonder if there's some more capacitors on another board that's involved with the loading/playback mechanism?

Also I noticed that when the VCR attempts to power up the display screen shows "camera" on the readout which I'm not sure if that's normal or not but I'm wondering if that's maybe something that might be something to do with what's going on with the VCR and why its acting up?

djfivos · #66 05-27-2022, 08:37 PM

Quote:

Originally Posted by vortalexfan

Also I noticed that when the VCR attempts to power up the display screen shows "camera" on the readout which I'm not sure if that's normal or not but I'm wondering if that's maybe something that might be something to do with what's going on with the VCR and why its acting up?

Is the input selector switch set to camera?

djfivos · #67 05-28-2022, 09:29 AM

Quote:

Originally Posted by vortalexfan

I did find a service manual for this VCR (its the Sam's version.)

I found the correct page for the Motor Drive Circuitry, hopefully that will help others follow along.

Looks like the PV-1730 uses the same motor drive ICs as the portable PV-8000 so this schematic might be useful although the board itself is obviously different.
PV-8000 motor drive schematic 1.jpg

PV-8000 motor drive schematic 2.jpg
EDIT: Because the resolution of the attachments is garbage, here's the links for the full-res png files:
https://drive.google.com/file/d/1Xge...ew?usp=sharing
https://drive.google.com/file/d/1LGu...ew?usp=sharing

vortalexfan · #68 05-30-2022, 05:54 PM

Quote:

Originally Posted by djfivos

Is the input selector switch set to camera?

No, it wasn't it was set to the Line Input mode (which apparently triggers the "camera" light on the VFD Display readout, which is the same thing that happens when its actually set to "camera" mode.)

Anyways, I take it that the "Servo Board" also has some influence on the functionality of the VCR's loading/playback mechanism? If so could it be possible that there might be some bad caps on that board as well causing some issues?

djfivos · #69 05-31-2022, 07:48 AM

Quote:

Originally Posted by vortalexfan

No, it wasn't it was set to the Line Input mode (which apparently triggers the "camera" light on the VFD Display readout, which is the same thing that happens when its actually set to "camera" mode.)

Anyways, I take it that the "Servo Board" also has some influence on the functionality of the VCR's loading/playback mechanism? If so could it be possible that there might be some bad caps on that board as well causing some issues?

Generally the servo circuit is what controls the speed and phase of the capstan and drum motors. This machine being fully direct-drive will have an extra servo board for the reel motors. Loading issues are usually caused by dirty mode encoder switches, gummed-up mechanisms or missing/low power supply voltages. Since you have the Sam's, have you verified that the voltages from the power supply are correct?

vortalexfan · #70 06-01-2022, 03:32 AM

Quote:

Originally Posted by djfivos

Generally the servo circuit is what controls the speed and phase of the capstan and drum motors. This machine being fully direct-drive will have an extra servo board for the reel motors. Loading issues are usually caused by dirty mode encoder switches, gummed-up mechanisms or missing/low power supply voltages. Since you have the Sam's, have you verified that the voltages from the power supply are correct?

I did check the voltages and the seemed to be where they were supposed to be. I did notice though in the Sam's that there is a Voltage regulator transistor for the supply reel motor which (which seems to be the only part of the motor drive board that has a voltage regulator transistor), I wonder if that might of failed and that's what's causing the supply reel motor to malfunction, either that or some bad capacitors on another board somewhere in the VCR.

Also I was looking at the Servo/Control Board for this VCR in the Sam's and it seems that it does indeed control the take-up and supply reel motors as well besides the capstan and drum motors.
So again I think I might take a look at that board for some bad capacitors with my ESR meter.

vortalexfan · #71 06-01-2022, 04:05 PM

Well I took the Servo Circuit Board out and looked it over closely and when I was checking some of the electrolytics on the board, I noticed what looked like a dip or low spot in the board around one of the plastic stand-offs and so I looked at it closely and sure enough the board has several cracks in it that go through to the traces and so I think that the reason why this VCR isn't working is because of the cracks in the Servo Board.

Unfortunately I think this VCR is a lost cause unless someone has a donor board from a junker VCR that they'd be willing to send me or know of one somewhere for sale...

djfivos · #72 06-01-2022, 04:26 PM

Quote:

Originally Posted by vortalexfan

I did check the voltages and the seemed to be where they were supposed to be. I did notice though in the Sam's that there is a Voltage regulator transistor for the supply reel motor which (which seems to be the only part of the motor drive board that has a voltage regulator transistor), I wonder if that might of failed and that's what's causing the supply reel motor to malfunction, either that or some bad capacitors on another board somewhere in the VCR.

Also I was looking at the Servo/Control Board for this VCR in the Sam's and it seems that it does indeed control the take-up and supply reel motors as well besides the capstan and drum motors.
So again I think I might take a look at that board for some bad capacitors with my ESR meter.

You can measure the junctions of the transistor in the diode test mode of a multimeter. I don't know if this model is supposed to run the supply and/or take-up reel motor when you turn it on as we didn't have a PV-1730 equivalent model here in Europe. Does the front loading mechanism accept tapes?

vortalexfan · #73 06-13-2022, 07:16 PM

Quote:

Originally Posted by djfivos

You can measure the junctions of the transistor in the diode test mode of a multimeter. I don't know if this model is supposed to run the supply and/or take-up reel motor when you turn it on as we didn't have a PV-1730 equivalent model here in Europe. Does the front loading mechanism accept tapes?

No it doesn't accept tapes into the VCR when you try to load the tapes into the VCR, that's because (at least in USA models) the VCR has to be powered on in order for it to be able to load a tape into the mechanism, and if the VCR refuses to power on (goes into safety shut-down mode) then the VCR loading mechanism will not load tapes.

And as a little update, unfortunately I found several broken traces on the main control board of the VCR (the board that contains the Servo Circuit, Index Circuit, and the System Control Circuits) that were from some cracks that I found on the circuit board that were around a couple of the plastic standoffs that were for supporting the board against the case when you installed the board into the case.

I'm going to see if there's any way to repair those traces, if not I'll see if there's a board for this VCR available on feebay for sale.

djfivos · #74 06-16-2022, 04:02 PM

Quote:

Originally Posted by vortalexfan

No it doesn't accept tapes into the VCR when you try to load the tapes into the VCR, that's because (at least in USA models) the VCR has to be powered on in order for it to be able to load a tape into the mechanism, and if the VCR refuses to power on (goes into safety shut-down mode) then the VCR loading mechanism will not load tapes.

And as a little update, unfortunately I found several broken traces on the main control board of the VCR (the board that contains the Servo Circuit, Index Circuit, and the System Control Circuits) that were from some cracks that I found on the circuit board that were around a couple of the plastic standoffs that were for supporting the board against the case when you installed the board into the case.

I'm going to see if there's any way to repair those traces, if not I'll see if there's a board for this VCR available on feebay for sale.

It will more than likely be a single-layer board so severed traces will be easy to repair. Can you upload close-up pictures of the damaged traces?

vortalexfan · #75 06-16-2022, 04:27 PM

Quote:

Originally Posted by djfivos

It will more than likely be a single-layer board so severed traces will be easy to repair. Can you upload close-up pictures of the damaged traces?

Yes, thankfully it is a single layer board (traces only on one side) so yes I think it should be able to be repaired using the Shango method.

I'll post a picture of the broken traces when I get back from work later tonight.