Sony KD-34XBR960 (DA-4 chassis) 7 blinks no HV...Help me understand!

[Electronic M]

So this is my second DA-4 chassis HD-CRT Sony I still have the old one and it still works so I can check voltages on the old one.
The new one was being a good set until a little over a week ago when it wouldn't fully power on (HV wouldn't come up and got 3 relay clicks instead of 1) and gave me the the 7-blink error code. (My old one did the same when the MCZ3001 for the HV was failing and came right back after a new chip was installed.) Not having time to immediately deal with the issue looking at threads on this I figured out I could leave it unplugged overnight and it would self heal.... About a day ago it refused to self heal.

About 8 hours ago I got to work and replaced the MCZ3001D (IC8002) with an IC socket and a new spare...It didn't fix it. I know the new chip is good because I can run it down to my old working set plug the chip in and the other set will work fine. I'm fairly sure the other MCZ in the set (the DA-4 uses 2 MCZ chips) IC6501 is good because it supplies the bias voltages that circuits like the blink error circuit use to operate.
So far I know that the 15V line that feeds the anode of D8006 is matches voltage between the working and dead sets. I've confirmed fusible resistors R8201, 8051, 8061, 8058, and 6510 are good. I've also changed caps C8025, 8024, 8031, and 8033 and it's made no difference. I can also confirm the drain supply voltage to Q8014 is present.
The only odd thing I found is the voltage on pin 8 of MCZ (IC8002) seems to be 2V higher on the dead set... I'm not sure what would cause that.

I haven't done a full voltage comparison between both chips. It kinda scares me taking measurements on the chip in the good set as I'm worried I'll accidentally short pins on the good set taking measurements and end up with 2 dead sets instead of 1.

Does anybody have any troubleshooting advice? The dead set is my main daily driver TV and the longer it's out of commission the bigger the problem for me it becomes.

[vol.2]

Originally Posted by Electronic M

I haven't done a full voltage comparison between both chips. It kinda scares me taking measurements on the chip in the good set as I'm worried I'll accidentally short pins on the good set taking measurements and end up with 2 dead sets instead of 1.

The service manual should have voltages present on certain pins, under certain conditions.

It's nice to be able to compare to a working set, but in the case of such large, cumbersome chassis, I would probably just follow the SM

Also I think if you want any quality feedback you need to supply a schematic by linking an image to it. You can circle components you are talking about with red to call attention to them.

[Electronic M]

Originally Posted by vol.2

The service manual should have voltages present on certain pins, under certain conditions.

It's nice to be able to compare to a working set, but in the case of such large, cumbersome chassis, I would probably just follow the SM

Also I think if you want any quality feedback you need to supply a schematic by linking an image to it. You can circle components you are talking about with red to call attention to them.

The manual I'm using is 300 pages and can't be uploaded here and I can't find it online anymore. Here's a similar one that covers this set. https://www.manualslib.com/manual/83...55.html#manual (literally 1 minute on Google to find a manual).
The only voltages on the schematic I've been working off of are power supply rails there are literally none labeled on the chip... Maybe there's a chart somewhere but it isn't fun scowering a 300 page document for something that should be on the schematic.

[vol.2]

There's a chart on the righthand side of page 123 that lists every single pin of every IC on the board containing IC8001 and what should be present on the pin. There's lines in red on the schematic detailing important voltages to check for.

Ctrl+F>IC8001 inside the PDF

[zeno]

For manual
IIRC KV30HS420 was the common model with 2 IC's. Its SAMS 5162.
SAMS KV34..... models are 5429, 5398, 5460. No XBR's listed.
Try running on SAMS the chassis number SCC-### without varieties,
just the chassis family.

Only remember bad IC's & one or two FBT's on these sets. If the blink is for
over current its probably the FBT.
To test start the set a few times & see if the HOT is getting hot !
Another test is unplug the DGS, turn set on, watch the current.
If it goes over 1 amp usually FBT. Normal running current is @.8 amps.
And finally dont forget this has two or three grounds so gotta use the
right ground point for measurements.

73 Zeno
LFOD !

[Electronic M]

Originally Posted by vol.2

There's a chart on the righthand side of page 123 that lists every single pin of every IC on the board containing IC8001 and what should be present on the pin. There's lines in red on the schematic detailing important voltages to check for.

Ctrl+F>IC8001 inside the PDF

IC8002
Pin : Chart : Measures
1 : 2.6V : 0V
2 : 1.8V : 3.8V
3 : 2.2v : 1.7
4 : 2.5v : 2.3
6 : 0.0v : 0
7 : 4.6v : 0.141
8 : 17.9 : 17.6
9 : 0.0v : 0
10 : 10.5 : 10.5
12 : 4.8 : 0
14 : 151.8 : 0.03
15 : 142.2 : 110.6
16 : 146.3 : 133.8
18 : 306.1 : 4.1

IC8001 is a tiny surface mount under the board and is a lot less fun to measure than the through hole dips I've been messing with.
Pin : chart : measures
1 : 0.1v : 0.05
2 : 2.5v : 2.5
3 : 2.1v : 0.2
5 : 2.3v : 0.3
6 : 2.5v : 2.5
7: 0.0 : 0
8 : 17.5 : 17.5

Does this tell you anything as to what's wrong?

I should add that on some power ups it is degaussing.

[Electronic M]

Originally Posted by zeno

For manual
IIRC KV30HS420 was the common model with 2 IC's. Its SAMS 5162.
SAMS KV34..... models are 5429, 5398, 5460. No XBR's listed.
Try running on SAMS the chassis number SCC-### without varieties,
just the chassis family.

Only remember bad IC's & one or two FBT's on these sets. If the blink is for
over current its probably the FBT.
To test start the set a few times & see if the HOT is getting hot !
Another test is unplug the DGS, turn set on, watch the current.
If it goes over 1 amp usually FBT. Normal running current is @.8 amps.
And finally dont forget this has two or three grounds so gotta use the
right ground point for measurements.

73 Zeno
LFOD !

I'm going to stick with the factory manual. I don't have any Sam's above 1800 as typically 1970s Zenith Chromacolor II sets are the only solid state sets I'll touch, don't have budget to be buying from Sam's.

I had to turn it on a dozen times (goes into shutdown within 2-3 seconds so measuring 26 pins takes time) to take measurements and the flyback FETs stayed cool.

EDIT: Also looking at the schematic the Horizontal deflection doesn't come from the flyback on the DA-4 sets. The flyback only makes HV. And the horizontal sweep is it's own independent circuit separate from the HV supply for the CRT.....Sort of like a late 1940's electrostatic TV...What's old is new again.

[Electronic M]

So I got impatient and switched to plan B...A few years ago someone here parted out another DA-4 chassis set and I had a spare sweep board I bought off of them. It was supposed to be a good board and it turned out to be. I had to figure out how to swap some stablock connected wires that go from the flyback to the neck board and I had to steal the 2 large 1200uF 250V rectified line capacitors (I stole them off the spare board for a project years ago) off the riginal board for the replacement board.

The new rev D board is a year newer than the rev B original but the set now works. Horizontal is about 2-3" small on both sides and vertical is down an inch top and bottom. There's minor focus and issues and 1/4" of horizontal fold over on the right, but I'm confident I can at least fix the underscan (I've been in the service menus to minimize overscan before). With luck I'll have completely bailed my self out of this mess in a little bit....Sucks I now don't have a good spare board but at least I didn't have to kill my spare set to get the main one going.

IMG_20240921_221555566 by Tom Carlson, on Flickr

[Electronic M]

Well I think the spare board may not be up to snuff... I can't eliminate the horizontal underscan with HSIZ maxed out and that's a deal breaker. Horizontal linearity is kinda meh too, and the only way to cure the foldover was to set the HPOS to max which de-centers the clipping of the active image (I think the DSP in the set digitizes the signal then tries to scale it to the raster). It's possible my spare board may have come from a set with a smaller CRT (KD-30XS maybe) and isn't designed/setup to work with my set, or maybe it is defective in some way.

IMG_20240922_001048819 by Tom Carlson, on Flickr
IMG_20240922_001033745 by Tom Carlson, on Flickr

There's about 1.5" of underscan on the left and 0.5" on the right.
These are the settings edits I made to get from the last posts picture to the above 2 pictures.
D1
VPOS was 24 now 25
VSIZ 23 now 34
VSCO 7 now 3
VPIN 20 now 13
D2-D3
HCNT 40 now 28
HPOS 29 now 63
HSIZ 41 now 63
SLIN 4 now 0
MPIN 10 now 15
PIN 9 now 6
UCP 42 now 37
LCP 36 now 35
LANG 24 now 22
VBOW 27 now 24
TBLK 4 now 3
BBLK 6 now 0
AKBT 16 now 6
MID1
DVPH 20 now 24

Not sure where I should go from here...I think there are 3 paths:

1.) I could go back and do some more work on the dead board if someone can give me some advice on what to change or test.
2.)I could try and improve the spare board that is %90 working in it now if anyone has any good suggestions for that. (unless I can find something on the schematic that changes with different size CRT's I've done everything I can think of).
3.)I could also try taking the other working sweep board from my spare working KD-34XS955 and install it in this set (once I figured out the release for the connections board swapping became easy) and see if it is a better match that service menu settings can make as good as the original board.

I'm probably going to default to path 3 if nobody has any suggestions.
The XS955 has sat unused in the garage for several months since the XBR960 took it's place in my upstairs TV room. I'm OK if the 955 ends up with a working but sub-par sweep board (I just want the 955 working so if the 960 breaks again I have the 955 to use for comparison/parts) as long as the 960 works as good as it was before it died. Given there's a flight of stairs separating the 2 sets the 955 is probably never going back in the upstairs TV room.

[Electronic M]

Well I went with path 3 and the 960 is now probably working the best it has since I've owned it.
In the course of futile attempts to use menu settings to make that last spare incorrect (or possibly damaged) but functional board fill the screen I learned some new menu items that helped me better minimize overscan with the correct board.

The garage KV-34XS955 is going to have to live with the wrong board, but finally my daily driver KD-33XBR960 is back to and better than normal.