The patient is a JVC BR-S611U. This is an old professional SVHS edit
VCR. It loads okay, and positions the tape in the "half loaded"
position. No response to play, fast forward, or rewind. On eject, the
tape is not retracted back into the cassette. Using an empty cassette
shell, I can see that there's never any movement of the supply or
take-up reels.

Any suggestions on how to proceed? This went to a shop, which claimed
there was a power supply problem and the deck was not worth repairing.
The owner is a friend of mine and asked me to have a look at it.

Hi David...I have had patients with a similar problem. This sounds like
either a a
href="http://www.serverlogic3.com/lm/rtl3.asp?si=11&k=power%20supply"
onmouseover="window.status='power supply'; return true;"
onmouseout="window.status=''; return true;"power supply/a issue or a
mode switch issue. As you have seen, there are many fuses in the power
supply, and I assume you have checked that they are not only working,
but also that they are of the correct rating. If so, the best way to
rule out a power supply issue is to swap in another power supply board
if you can get access to another machine. In my opinion, the Achilles
heel of both the BR-S811U and BR-S611U is the mode switch. It is very
sensitive to correct positioning, and if the unit gets knocked, the
machine will half-load, then give an error signal (like error 32) and
eject the tape. The switch is under the transport and is a small board
held in place with one screw. Hope that is of some help.

VCR Gymnast wrote:
Hi David...I have had patients with a similar problem. This sounds like
either a a
href="http://www.serverlogic3.com/lm/rtl3.asp?si=11&k=power%20supply"
onmouseover="window.status='power supply'; return true;"
onmouseout="window.status=''; return true;"power supply/a issue or a
mode switch issue. As you have seen, there are many fuses in the power
supply, and I assume you have checked that they are not only working,
but also that they are of the correct rating.

Yes, I've checked them. I'm not sure what the correct test point
voltages are, though, so I can't verify anything else about the power
supply.

In my opinion, the Achilles
heel of both the BR-S811U and BR-S611U is the mode switch. It is very
sensitive to correct positioning, and if the unit gets knocked, the
machine will half-load, then give an error signal (like error 32) and
eject the tape. The switch is under the transport and is a small board
held in place with one screw. Hope that is of some help.

Hmm! We might be on to something here. I'm getting warning code 72
when I load a tape. I didn't include this information in the original
post because I hadn't realized this deck had a warning code display at
the time. Is there a reference somewhere for what these codes mean?

David Brodbeck wrote:
The patient is a JVC BR-S611U. This is an old professional SVHS edit

VCR. It loads okay, and positions the tape in the "half loaded"
position. No response to play, fast forward, or rewind. On eject,
the
tape is not retracted back into the cassette. Using an empty
cassette
shell, I can see that there's never any movement of the supply or
take-up reels.

Check/ clean /replace Mode switch. almost sure to be that.
IC protector on drum motor ic has caused me the occasional problem in
jvcs.

-Ben

b wrote:
Check/ clean /replace Mode switch. almost sure to be that.
IC protector on drum motor ic has caused me the occasional problem in
jvcs.

I'm having a little trouble finding the mode switch. VCR Gymnast said
it's a small board under the transport, secured with a single screw.
I'm looking at the underside of the transport, and I'm not sure where it
is. I see a small, vertically mounted board, just forward of the drum
motor, with two microswitches on it and a three-conductor cable...is
that what I'm looking for?

That is it!! See if the microswitches are being properly activated. I
will let you know what error 72 is, but it will probably go away once
the mode switch is operating correctly.

VCR Gymnast wrote:
That is it!! See if the microswitches are being properly activated. I
will let you know what error 72 is, but it will probably go away once
the mode switch is operating correctly.


The one closest to the bottom of the VCR (i.e., farthest from the
transport) is actuating fine, and checks out electrically. It's not
clear to me when the one above it is supposed to actuate. It never
moves, and I can't seem to spot the lever that's supposed to move it.

I know what you mean. I suggest to loosen the screw just enough so you
can rotate the board slightly counterclockwise (I think). After each
small rotation, try to re-insert the cassette. The second microswitch
gets activated during the full load, which is why you haven't seen its
action yet. Keep posting on your progress.

VCR Gymnast wrote:
I know what you mean. I suggest to loosen the screw just enough so you
can rotate the board slightly counterclockwise (I think). After each
small rotation, try to re-insert the cassette. The second microswitch
gets activated during the full load, which is why you haven't seen its
action yet. Keep posting on your progress.


No luck, I'm afraid. No matter how I position it, I still get either
warning 72 or warning 73. I noticed the switches were a bit loose on
their bracket, and removed the switch assembly to tighten them, but when
I reinstalled it and tried adjusting it again I still got the same
results. I checked the switches, and electrically they seem to work fine.

Hmmm....OK, I will get back to you tomorrow about what the warning
codes mean. Just to be sure I have it right, is the machine making any
progress beyond half-load? If not, it may be that these warnings have
to do with reel motors or the drum motors failing to start.

VCR Gymnast wrote:
Hmmm....OK, I will get back to you tomorrow about what the warning
codes mean. Just to be sure I have it right, is the machine making any
progress beyond half-load? If not, it may be that these warnings have
to do with reel motors or the drum motors failing to start.


No, it doesn't.

OK, here is some information that promises to be useful:

Warning 72 and 73: In the unloading state, these warnings are caused
when reel motor rotation stops for ~2 seconds and there is no output of
reel frequency generator (FG) pulse. In the loading state, they are due
to no output of reel FG pulses while 14 capstan pulses are counted.
Warning 72 relates to no supply reel FG (Pin 33B of CN1 on the system
control board) while warning 73 relates to no take-up reel FG (Pin 34B
of CN1).

The corresponding Test Point (TP) voltages on Servo board 2 are TP7 for
the supply reel and TP9 for the take-up reel. Both should measure 6.00
VDC.

To check the power supply regulator board, here are the TP voltages
that should be present:
TP1: +11.7 +/- 0.3 VDC
TP2: +9.0 +/- 0.3 VDC
TP3: +5.1 +/- 0.2 VDC
TP4: +5.1 +/- 0.2 VDC
TP5: -14.0 +/- 1.0 VDC
TP6: +10.3 +/- 0.5 VDC
TP7: +16.5 +/- 1.0 VDC
TP8: +18.0 +/- 1.0 VDC
TP9: +12.0 +/- 0.4 VDC
TP10: +15.0 +/- 0.4 VDC

Are all these signals present at the proper level?

VCR Gymnast wrote:
The corresponding Test Point (TP) voltages on Servo board 2 are TP7 for
the supply reel and TP9 for the take-up reel. Both should measure 6.00
VDC.

To check the power supply regulator board, here are the TP voltages
that should be present:

Thanks a lot for that info. It will be a couple of days before I can
run these tests, but I'll get back to you once I have. I assume these
are all referenced to the chassis?

VCR Gymnast wrote:
The corresponding Test Point (TP) voltages on Servo board 2 are TP7 for
the supply reel and TP9 for the take-up reel. Both should measure 6.00
VDC.

I've got 0.10V for both.

To check the power supply regulator board, here are the TP voltages
that should be present:
TP1: +11.7 +/- 0.3 VDC

I've only got 0.87VDC.

TP2: +9.0 +/- 0.3 VDC

0.04VDC.

TP3: +5.1 +/- 0.2 VDC
TP4: +5.1 +/- 0.2 VDC
TP5: -14.0 +/- 1.0 VDC
TP6: +10.3 +/- 0.5 VDC
TP7: +16.5 +/- 1.0 VDC
TP8: +18.0 +/- 1.0 VDC
TP9: +12.0 +/- 0.4 VDC

TP3-TP9 are all in spec.

TP10: +15.0 +/- 0.4 VDC

-0.003V.

Looks like I've got a power supply issue, all right. At least it's a
linear supply instead of a switcher, from the looks of things. At this
point it would be nice to have access to a schematic; I'm guessing TP1,
TP2, and TP10 are all derived from a common source voltage, somewhere.

Yes, in my experience with these decks, it is almost always the
regulator board. I can scan and e-mail you the schematic of the power
supply/regulator board tomorrow. In the meantime, I suggest you take
the board out (there are about 20 cables to disconnect. Once the board
is out, I would recheck all the fuses on that board, and any other
fuses you see on the board next to it.

VCR Gymnast wrote:
Yes, in my experience with these decks, it is almost always the
regulator board. I can scan and e-mail you the schematic of the power
supply/regulator board tomorrow. In the meantime, I suggest you take
the board out (there are about 20 cables to disconnect. Once the board
is out, I would recheck all the fuses on that board, and any other
fuses you see on the board next to it.


Okay, great. I really appreciate all your help.

David...I need your e-mail so I can send you an attachment...

It turned out that the problem here was a cold solder joint on one of
the connectors on the Regulator (power supply) board. Now fixed and
working well. Case closed.