Sony PVM-1954Q retrace issue

[[email protected]]

Recently got a sony PVM-1954Q that had some bad electrolytics in
it.

I recapped the A board, (132 caps, I won't be doing that anytime
soon again) fired it up and did the alignments according to the
service manual (I have that as well).

The only issue that 'remains' is there are 3 lines, one each for
the red, blue, and green guns at the very top of the picture.
This is evident in all modes, 4:3, 16:9, and underscan. You cant
'see' it in 4:3 mode as it's at the very top of the display but
it's there if you move the picture with the vertical centering.

Wave forms and voltages look normal on IC506, 502, Q507 and Q505.

Picture looks good. All other alignments appear to work correctly.

Just can't get rid of those retrace lines. They look abnormal when
you use the 16:9 or underscan modes.

Anyone ever run across anything like this ?

 

[carneyke]

Ismus be your lucky day ! C584 causes retrace at top of CRT, distorted
(curved corners) in underscan mode = C572 & C592 causes a noisy
picture with excessive jitter. You didn't change all the capacitors or
not in the deflection area. Good Luck

 

[Airioch]

Ismus be your lucky day ! C584 causes retrace at top of CRT, distorted
(curved corners) in underscan mode = C572 & C592 causes a noisy
picture with excessive jitter. You didn't change all the capacitors or
not in the deflection area. Good Luck

Ummmm, yes, I actually replaced all the electrolytics in the chassis
with the exception of one of them, C1515, there's some modification on
the trace side of the board that's covering that particular cap.

Didn't replace any of the polystyrene or dipped mylar..

I'll poke around in that area of the chassis, so some resistance checks
on the associated resistors..

Thanks for the reply..

airi-

 

[Airioch]

Ismus be your lucky day ! C584 causes retrace at top of CRT, distorted
(curved corners) in underscan mode = C572 & C592 causes a noisy
picture with excessive jitter. You didn't change all the capacitors or
not in the deflection area. Good Luck

Removing and measuring the components in that area shows them
all to be well within tolerance with one possible exception.

L515 as indicated on the schematic should be, at least according to
what's on the paper, 12uH. Looking in the parts list only gives a sony
part number, going by what's indicated on the schematic, L515 is way out
of spec, I'm measuring 12.38mH (wavetek LCR55).

I'm hoping that it's a misprint on the schematic, that's a pretty large
amount to be out, I'd expect more than a couple of retrace lines at the
top of the display..

airi-

 

[[email protected]]

Recently got a sony PVM-1954Q that had some bad electrolytics in
it.

I recapped the A board, (132 caps, I won't be doing that anytime
soon again) fired it up and did the alignments according to the
service manual (I have that as well).

The only issue that 'remains' is there are 3 lines, one each for
the red, blue, and green guns at the very top of the picture.
This is evident in all modes, 4:3, 16:9, and underscan. You cant
'see' it in 4:3 mode as it's at the very top of the display but
it's there if you move the picture with the vertical centering.

Wave forms and voltages look normal on IC506, 502, Q507 and Q505.

Picture looks good. All other alignments appear to work correctly.

Just can't get rid of those retrace lines. They look abnormal when
you use the 16:9 or underscan modes.

Anyone ever run across anything like this ?

Firts thing, you went WAY overboard on the caps thing. As others said,
C572 and C584 are the most common bad ones. There are a couple others I
check in the sweep area, C588, C590 and a few others. Get an ESR meter
and you'll save scads of time.

Your 'retrace' lines are not retrace lines. Those are the beam current
feedback measurements and if you get rid of them, it will look
terrible. In NTSC they fall on lines 17,18,19 - RGB respectively. You
measure TP403 with a scope and set G2 until the lowest value of those 3
lines is +1.35 volts.

Do you have the service manual? It explains most of this though the
schematics are drawn poorly.

GG

 

[Airioch]

Firts thing, you went WAY overboard on the caps thing. As others said,
C572 and C584 are the most common bad ones. There are a couple others I
check in the sweep area, C588, C590 and a few others. Get an ESR meter
and you'll save scads of time.

I'll have to get an ESR meter ( I don't normally work on monitors for
folks..), always good to have tools laying about when you need them.


Checked all the component values in the vertical drive area. All of them
are well within tolerance. C576,584,587,588,589,590,591,586 (I've
replaced all the electrolytics but pulled the ones in the section and
checked them anyway..) All the resistors R1515,1522,1523,1527,1528,1531
all check out as well, almost spot on the value as stated on the
schematic and in the parts list. Q513 and 515 appear to be okay as well,
I've getting a pretty close hfe reading on both of them, 157 I believe
was the figure, no leakage.

Your 'retrace' lines are not retrace lines. Those are the beam current
feedback measurements and if you get rid of them, it will look
terrible. In NTSC they fall on lines 17,18,19 - RGB respectively. You
measure TP403 with a scope and set G2 until the lowest value of those 3
lines is +1.35 volts.

Looked at that, I'm coming up with 1.35 as measured on the lowest of the
set, tried dropping it lower, still see the aforementioned lines.

Are you indicating that those lines are supposed to be there and visible
? (I've never seen this monitor or one like it run before so this is new
to me... I'm just going by what the owner was indicating, "one day they
were not there, now they are.." )

Do you have the service manual? It explains most of this though the
schematics are drawn poorly.

If you can call it a service manual, yes, I have it. Test points not
labeled or not listed, signals present on the test points not indicated,
heck I think I've only found one or two of them on the schematic itself.

The G2 alignment, I kept looking for the Screen VR reference, ahhhh,
look at the S board, look at the CRT, look, G2 and it's associated
adjustment. Pretty poorly put together.

All the components I've checked are within 5% of specified values, even
the ceramic disc caps are within 10%.

I appreciate the responses.

airi--

 

[[email protected]]

I'll have to get an ESR meter ( I don't normally work on monitors for
folks..), always good to have tools laying about when you need them.


Checked all the component values in the vertical drive area. All of them
are well within tolerance. C576,584,587,588,589,590,591,586 (I've
replaced all the electrolytics but pulled the ones in the section and
checked them anyway..) All the resistors R1515,1522,1523,1527,1528,1531
all check out as well, almost spot on the value as stated on the
schematic and in the parts list. Q513 and 515 appear to be okay as well,
I've getting a pretty close hfe reading on both of them, 157 I believe
was the figure, no leakage.

Looked at that, I'm coming up with 1.35 as measured on the lowest of the
set, tried dropping it lower, still see the aforementioned lines.

Are you indicating that those lines are supposed to be there and visible
? (I've never seen this monitor or one like it run before so this is new
to me... I'm just going by what the owner was indicating, "one day they
were not there, now they are.." )


If you can call it a service manual, yes, I have it. Test points not
labeled or not listed, signals present on the test points not indicated,
heck I think I've only found one or two of them on the schematic itself.

The G2 alignment, I kept looking for the Screen VR reference, ahhhh,
look at the S board, look at the CRT, look, G2 and it's associated
adjustment. Pretty poorly put together.

All the components I've checked are within 5% of specified values, even
the ceramic disc caps are within 10%.

I appreciate the responses.

airi--

I just looked at 1354 at my bench. The call lines are only visible in
underscan regardless of pulse cross.

GG

 

[Airioch]

I just looked at 1354 at my bench. The call lines are only visible in
underscan regardless of pulse cross.

Hmmm, I see them in underscan and 16:9 modes on the 1954, 4:3 of course
they are at the top out of visible sight.

The main reason I'm 'worried' about them is I was told one day they
weren't.

They were visible in 4:3 until I replaced the Electrolytics, there was a
slight vertical foldover and the caps fixed that (well one of them did).

again, I appreciate the response.

Recommend any good ESR testers ?

airi--

 

[[email protected]]

Hmmm, I see them in underscan and 16:9 modes on the 1954, 4:3 of course
they are at the top out of visible sight.

The main reason I'm 'worried' about them is I was told one day they
weren't.

They were visible in 4:3 until I replaced the Electrolytics, there was a
slight vertical foldover and the caps fixed that (well one of them did).

again, I appreciate the response.

Recommend any good ESR testers ?

airi--

You're right on the 16:9 mode. I rarely use it so I forgot.

We use the 'Capacitor Wizard' which works very well but I heard it was
no longer available. Check threads on ESR meters. There is a lot of
info on this.

GG

 

[[email protected]]

Hmmm, I see them in underscan and 16:9 modes on the 1954, 4:3 of course
they are at the top out of visible sight.

The main reason I'm 'worried' about them is I was told one day they
weren't.

They were visible in 4:3 until I replaced the Electrolytics, there was a
slight vertical foldover and the caps fixed that (well one of them did).

again, I appreciate the response.

Recommend any good ESR testers ?

airi--

BTW I also forgot that those cal lines were always there so if you have
ops saying otherwise, they just didn't notice. I call it the dripping
faucet syndrome. It's REAL hard to go back to not hearing the drip.

The Sony broadcast BVM series also does beam feedback and has those
lines at the start of V sweep. If colorists can get over it, EVERYBODY
can because those folks are the most demanding group there is.

GG

 

[Meat Plow]

You're right on the 16:9 mode. I rarely use it so I forgot.

We use the 'Capacitor Wizard' which works very well but I heard it was no
longer available. Check threads on ESR meters. There is a lot of info on
this.

GG

I use a BK 881 ESR and it seems to do a great job.

 

[Homer J Simpson]

Recommend any good ESR testers ?

Elektor published a design for a Cap/ESR meter.

John's Jukes in Vancouver BC sells a kit which has been recommended.

 

[Airioch]

BTW I also forgot that those cal lines were always there so if you have
ops saying otherwise, they just didn't notice. I call it the dripping
faucet syndrome. It's REAL hard to go back to not hearing the drip.

Hmmmmm, well, I don't like chasing ghosts... I suppose it would have
helped to have viewed the monitor before all this started. That would be
in a perfect world.

The Sony broadcast BVM series also does beam feedback and has those
lines at the start of V sweep. If colorists can get over it, EVERYBODY
can because those folks are the most demanding group there is.

I'm working on this one for a video editor friend of mine, he's awfully
demanding Sometimes pretty hard on the equipment too, but amazing to
watch work.

I'll take a look at ESR meters that have been suggested in the thread. I
actually have most of the Elecktor issues that were released here in the
states, to many neat articles and projects to pitch them. I'll go back
and take a look there as well.

Thanks for the response.

airi--

 

[Airioch]

Elektor published a design for a Cap/ESR meter.

John's Jukes in Vancouver BC sells a kit which has been recommended.

I'll have to take a peek, I have a bunch of the Elektor issues that
were released here in the States, then they went away, not enough
circulation I suppose.

I'll take a peek and the suggestions you all have made.

Thanks for the information/suggestions.

airi--

 

[Homer J Simpson]

I'll take a look at ESR meters that have been suggested in the thread. I
actually have most of the Elecktor issues that were released here in the
states, to many neat articles and projects to pitch them. I'll go back
and take a look there as well.

I can post the Elektor article if you want it, but IIRC it uses a custom PIC
chip so you'll need to source that.

 

[Airioch]

Just can't get rid of those retrace lines. They look abnormal when
you use the 16:9 or underscan modes.

Anyone ever run across anything like this ?

It's off the bench, The 'retrace' lines were indeed, as pointed out,
supposed to be there.

There was a slight mis-communication on exactly where the 'retrace'
lines were occurring on the display. Initially they were showing up
on the display due to the 'foldover' issue (caps fixed this). I saw
the foldover in the 4:3 mode and they pointed at the 'lines' and said
there weren't there, now they are, make 'em go away. Ha...

Did the basic alignment on the monitor, tweaked the centering with
a couple of different 'live' signals, let my friend look at it and
go through all the modes on it and he's happy.

I appreciate all the assistance with this issue.

Whatta ya know, USNET groups do still have some use left in them.

airi--