Help with repair of Turbo Express

[jelloslug]

I working on a TE that needed a full cap replacement.  Everything was going well, all the caps went in OK and all the standard issues were repaired.  I closed it back up, powered it up and the first thing that happened was that the brightness wheel no longer worked but the brightness was still OK.  Very shortly afterward the backlight started flickering and the unit shut down.  It would power back for for no more than half a second and then it was all dead.  The 1 amp fuse was blown so I check the board over for shorts and replaced the fuse.  With the fuse replaced the backlight would come on and that was it.  The new fuse does not blow but nothing else works.  And pointers on where to looks would be great.

[Keith Courage]

Try using new batteries or an ac adapter. Typically when the contrast wheel doesn't work it's because the batteries are low.

[jelloslug]

The batteries are not it, I put a fresh set in with no change.  Everything was working fine until I closed it up then everything stopped working right.

[thesteve]

check the 5V regulator for system function, and the 24V supply for the brightness issue.
the 5V can be found on most caps.
the 24V on 1 cap and 1 pin on the display

[jelloslug]

check the 5V regulator for system function, and the 24V supply for the brightness issue.
the 5V can be found on most caps.
the 24V on 1 cap and 1 pin on the display

I have 5V at every cap but I could not find 24V anywhere.

[thesteve]

controller must be connected for 24
pin3 of the screen is -24V

[turbokon]

You have a short somewhere, also double check polarity.

[turbokon]

Also check to see if the controller ribbons are connected probably.

[HercTNT]

Hoping for another happy ending, were pulling for you jello

[jelloslug]

Polarity is good and the controller ribbon is fine.  I'm not getting 24V at the video connector and the system still appears to be dead.

[jelloslug]

I went over both sides of the board looking for dead shorts and I could not find anything.  What caps have to be replaced when a unit usually won't power on? 

[thesteve]

any sound?

[jelloslug]

any sound?

Nothing.  Not from the speaker or the headphone jack, not even a pop when you turn the system on.  Both the speaker and the headphone jack were working properly before the problems started.

Also, just to clarify, when the system failed for the last time the game started and then just froze up after about a second, then the next few times when you turned it on you got just the backlight and then lastly nothing happened. I had to replace the AC jack so I'm wondering if I might have damaged some of the components under the gray glue on the back side of the board near where the pins on the AC jack poke through.

[thesteve]

the chipset and sound should work without the 24, its for the screen only.
the pop is from the amp, not the chipset.
what caps did you use?
and please check them for voltage (meter across cap power on)

[jelloslug]

the chipset and sound should work without the 24, its for the screen only.
the pop is from the amp, not the chipset.
what caps did you use?
and please check them for voltage (meter across cap power on)

The caps were a kit I bought specifically for the TE.  There is 5V on both sides of all the caps.