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also watch out for sub standard ic, i know there are bad la7837 on the market

in regards to cap kits of course you are dependent on the seller getting the kit correct - unlike one ms8-26 kit on the market where one of the most important caps is incorrect
 
When it comes to troubleshooting ICs, I have read of people using cold spray (maybe just a air duster turned upside down) and getting the ICs really cold and looking for any change. Might be a quick way to get a sanity check on that LA7853 or other questionable ICs.
Sounds dangerous.
also watch out for sub standard ic, i know there are bad la7837 on the market

in regards to cap kits of course you are dependent on the seller getting the kit correct - unlike one ms8-26 kit on the market where one of the most important caps is incorrect
Ok, so I replaced LA7853 again. No change. Still same vertically squashed rolling image. Chips are from a good trusted source.

I am going to check my solder job at CN102 again. See if anything is crossed up.

EDIT: Double checked my soldering job at CN102, nothing is crossed up. No solder bridges. It is fine. Also, I swapped neck boards with the other chassis, no change either. Here is my cap list. Please let me know if you see anything that is incorrect:

C101: 1uf 50v
C107: 22uf 50v
C201: 47uf 16v
C202: 47uf 16v
C203: 47uf 16v
C211: 2.2uf 50v
C212: 2.2uf 50v
C213: 2.2uf 50v
C220: 470uf 16v
C221: 100uf 35v
C222: 22uf 50v
C332: 10uf 250v
C402: 470uf 16v
C406: 1000uf 35v
C407: 100uf 35v
C408: 100uf 50v
C408: 100uf 16v
C409: 100uf 50v
C409: 100uf 35v
C451: 22uf 50V
C455: 10uf 50v
C456: 10uf 50v
C457: 10uf 50v
C458: 22uf 50v
C459: 22uf 50v
C503: 100uf 35v
C513: 10uf 250v
C515: 100uf 160v
c554: 1uf 50v
c555: 1uf 50v
C561: 47uf 16v
C562: 100uf 16v
C951: 180uf 100v
C952: 180uf 35v
C953: 47uf 160v
C954: 680uf 35v
C955: 180uf 25v
C956: 680uf 10v
C957: 10uf 50v
C958: 47uf 16v
 
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Success!!! (errrrr, somewhat).

IMG_1335.JPG
IMG_1337.JPG

While I was going through the MS9-29SU, grabbed the MS9-29T to do a comparison of one of the parts. Then noticed that the MS9-29T that I put aside had no solder around the HOT. I must have removed solder to reflow there the last time I touched it and forgot to reapply solder. No wonder why it was dead after I installed the new LA7853.

Decided to put aside the MS9-29SU and try my luck with the MS9-29T again. Recapped the vertical circuit and as I did this checked all the pulled caps with the BSide ESR02 Pro meter. They all checked out good. I recapped that area for good measure anyway and did nothing else. And whollah, she fired right up. I will finish recapping the chassis in full for good measure. Also, it is reassuring to know that the source I got the parts from ended being good. My steps are below in the spoiler.

Big thanks to the incomparable @gunblade for his virtuoso wisdom. And big thanks to @Hatsune Mike for the MS9 tube.

I will still work on the MS9-29SU (squashed vertically w/rolling screen) until that is resolved.

Symptom:
  • Dead - electrical static can be heard filling the tube upon power up, then monitor quickly can be heard discharging. No image is ever displayed on screen. No neck glow.
Actions Taken:
  • Replaced LA7837 - still dead
  • Replaced LA7853 - still dead but at this step, I errantly removed solder around HOT and did not reapply
  • Reapplied solder around HOT and recapped vertical circuit and she fired up again!
Caps in the vertical circuit that I replaced are coded below:
Code:
C407 100uf 35v
C408 100uf 35v
C409 100uf 35v
C958 47uf 16v
C406 1000uf 35v
C455 10uf 50v
C458 22uf 50v
C457 10uf 50v
C456 10uf 50v
C459 22uf 50v
C456 10uf 50v
C562 100uf 10v
C561 47uf 16v
C554 1uf 50v
C451 22uf 50v
C402 470uf 16v
C411 2.2uf 50v (bi-polar)
 
Oops, spoke too soon with the MS9-29T.

In the middle of soak-testing the monitor, it shut itself off after about 30 minutes. A quiet audible click can be heard as it does this. There was still neck glow (I believe) but no image on screen. After powering down completely, then turning it on quickly after, there was no image on screen but there was neck glow. Leaving it off for a good 5-10 minutes, then turning it back on then produced an image, but would shut down after 30 minutes or so.

At this point, I had not fully recapped the chassis. Only the vertical circuit was recapped. So then I did the obvious thing and recapped the entire chassis, save for C411 (bi-polar) and C503 as I did not have caps for those handy. Still, I am getting the random shut down. I am also noticing before the image shuts down, it is jittery.

Next Steps:
  1. I am going to pull C411 and C503 off the MS9-29SU which I just recapped and put it into the MS9-29T
    • EDIT - Done. No change
  2. Digging up info on checking B+, in case after replacing C411 and C503 does not fix the problem
    • EDIT - B+ is measuring a rock solid 75.61vdc. Measured with a Fluke meter
  3. Reading up on the info about the diodes around the flyback
  4. Reading up about the HOT
While I do have replacement HOT's handy, I want to avoid replacing the HOT as much as possible.
 
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See post #29.

Pulled HOT out of circuit and it is testing bad as far as I can tell. If I am not mistaken, HOT is NPN polarity and legs from left to right are: Emitter-Base-Collector (E-B-C). With DMM set to diode test, I get:
  1. Positive lead on Base - to either Emmitter or Collector, I get OL
    • I should have a reading on both these tests
  2. Negative lead on Base - to Emitter I get 0.4876, to Collector I get OL
    • I should get OL reading on both
  3. Postive lead on Collector, Negative lead to Emitter, I get OL
    • This is good
Based on these tests, HOT is bad and must be replaced. Also, I noticed as I pulled the HOT, there was no mica insulator. I'll add in the insulator with non-conducitve silicon paste once I can find my HOT's :thumbsup: .


Am I on the right track here?


EDIT: Pulled HOT off MS9-29SU hoping to use it for parts, it tests similarly. I don't have any HOT's handy so will have to put in an order somewhere.
 
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i did say replace caps in power supply, vertical and video b+ sections and check for bad solder joints before doing anything else

b+ should be 75v 15k and 118v 25k

if the HOT was bad it would not even power on
never had any diodes around flyback or flyback go bad on these
 
i did say replace caps in power supply, vertical and video b+ sections and check for bad solder joints before doing anything else
It is fully recapped and I checked a lot of the joints under magnification. I'll do it again.
b+ should be 75v 15k and 118v 25k
Yeap, I got 75.61v at 15khz
if the HOT was bad it would not even power on
never had any diodes around flyback or flyback go bad on these
Yeah, strange that it is turning on. But I pulled HOT out of circuit, it is definitely testing bad. Let me test with my other Fluke meter to be sure.

Also, I did swap neck boards. Seems there are differences between the the 29SU and 29t neckboards. Let me swap them back and report back.
 
Looks like I am testing it wrong. Pulled the diagram from the datasheet. So HOT's are good afterall:

2SC4692.JPG
 
Personally I test all transistors with the BSIDE ESR20. If it reports it as faulty, it is. If it doesn't, it most likely isn't.
 
Personally I test all transistors with the BSIDE ESR20. If it reports it as faulty, it is. If it doesn't, it most likely isn't.
HOT is good @nem. I was under the impression that since it was NPN, the pins were Emitter-Base-Collector. But after checking the datasheet, the pins are Base-Collector-Emitter. So note to self, NPN does not always imply that Negative-Positive-Negative follows that sequence on the actual transistor legs.

I put the HOT back in, re-installed the original neckboard, it still shuts down, then starts back up. Will check caps in HV circuit against 300wins list here. Perhaps I made a mistake in there somewhere. Will check fully for cold solder joints too. I am ooh so close.
 
The one cap I didn't replace was the filter cap (C911). I pulled it off the other chassis and reflowed solder just about every spot in the HV area and other places. I didn't see any cold solder joints but after firing it back up, there must have been some because I am just touching some chassis pots and the image jumps or flashes depending on the pot I am touching.

Soak testing it now. So far so good. There is lots of noise on the screen which I suspect is a grounding issue somewhere. So will do lots more reflowing after this 1-2 hour soak test.

EDIT: FINAL UPDATE ON THE MS9-29T

I can put a bow tie on this one. Image is stable after wiring groud to monitor frame. No longer goes into shut down. Chassis pots were reflowed. Image doesn't jump or flash as I touch them now. Erry thang lookin' gooooooot in da hood! I'll update the OP with a log.

I have found a suitable donor tube for the MS9 I want to test out before putting the the monitor into the New Astro City I picked up from KC. First game I want to play on it is Radiant Silvergun on the ST-V multi!

MS9-29SU is next. Need some parts to come in now that I sacked it for some parts for the 29T.
 
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Fantastic work! I am glad you documented your troubleshooting steps as it was helpful to read along and get an idea of where to look for various issues. Congrats on resurrecting that MS9; working on monitor chassis always gives me hesitation with the voltages involved.
 
BONUS: I may have found a suitable donor tube for the MS9-29. Curvature is perfect. Now that the chassis works, I can confirm compatiblity. It produces a beautiful image. I haven't checked fitment yet. But that is easy to solve. If too deep, mount behind frame ears. If too shallow, add washers.

IMG_1350.JPG
 

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MS9-29SU Status Update: WIP
  • Found broken solder pad and lifted track at pin 12 on U401 connecting to D403. Patted pad and trace down and reflowed solder at pin 12
    • Foolishly did not check continuity after completing this however
    IMG_1356.JPG
  • Reinstalled HOT with mica insulator and non-conductive silicon grease
  • Reinsalled C911 pulled from MS9-29T
Rolling vertically squashed image still prevelant.
  • Resistors already checked in vertical circuit
  • Both LAxxxx chips replaced
  • Save for C911, all caps replaced
  • Remote board used is known good
Next steps:
  1. Check continuity at lifted trace patch
  2. Reflow solder throughout vertical circuit
  3. Reflow solder at remote board harness
  4. Reflow solder at RGB header
  5. Reflow solder at chassis pots, particularly pots and parts in vertical circuit
  6. Recap vertical circuit again if necessary
  7. Cross fingers
 
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