MS8-26 Recap gone wrong

[geekmiki]

Hi,

I just got an Aero City with a MS8-26SU. The chassis worked, but after a few hours retrace lines appeared at the top of the screen, so I decided to do a recap since it most likely would solve that issue from what I read.
The recap went fine of both the chassis and the PSU. ALL caps were replaced with the same value that was on the chassis. The area around Q401 had clearly seen better days, it was quite oxidized, so quite a few joints were reflown in the process.
Upon startup after the recap, I got nothing and after a few seconds a vertical line. I decided to look at the deflection circuit and reflow again the solder joints that looked dodgy.
Tested again and absolutely nothing. No neck glow, no static, but B+ was working and the tube was being charged. After that, fuse at F902 (2A) would blow every time.

At that stage I took it over to @BuddyC so that he could double check my work and see if I had messed up something very obvious. He spent a while going over the board, reflowed a ton of solder joints, replaced R433 and R436 that looked very crusty (even though readings were ok), tested HOT (ok), looked for reversed caps, tested for shorts in the deflection circuit, etc

I tried to fire it up again after that and the fuse blew again.

Where to go from here?
Anything obvious I am missing and that could blow F902?

Thanks!

 

[BuddyC]

Post some pictures of the chassis and that crusty area around Q401. Maybe @nem sees something I didn’t.

 

[geekmiki]

Here you go

 

[BuddyC]

Is that a picture of before I did the clean up?

 

[nem]

Probably impossible to spot the fault from a picture.

Check the voltage regulator Q901.

Ideally you would have a working chassis and then you would start metering components methodically using the schematic that's available on the AO wiki, first on the faulty chassis and then on the working one. Eventually you should find the component that gives a different reading.

 

[Crunch]

Since it was working before the recap, it's highly likely something that went wrong during that process. Make 100% sure that all the cap orientations are correct. I found it easy to lift pads when I recapped my MS9s, it looks soldered in but when I gently push down on a cap, one of the legs pushes through the joint and needs to be repaired.

Hopefully you took before and after pics, maybe a solder blob landed somewhere and made a bridge?

 

[geekmiki]

Is that a picture of before I did the clean up?

That was before your clean up.

Probably impossible to spot the fault from a picture.

Check the voltage regulator Q901.

Ideally you would have a working chassis and then you would start metering components methodically using the schematic that's available on the AO wiki, first on the faulty chassis and then on the working one. Eventually you should find the component that gives a different reading.

Unfortunately, I do not have a spare chassis (otherwise half of my problems would be solved )
The chassis is being sent out for repair, since I have already spent way too many hours trying to figure out what could be wrong.

Thanks anyway.