Pentranic CH-288 - No Picture

[madmanlxl]

I've got a weird one that I can't quite work out.
I've got a 38" Tube with a CH-288 Chassis. It worked for about 5 mins after being not used and stored in the previous owners garage for about 8 years. After being on for 5 minutes I shut it off as the picture was dull so guessed it was going to be caps. Switched it back on just to double check and received a chirping sound. I Switched it off and checked the Chassis out.
Following was found and replaced.

C501 -- 200v 100uF -- Replaced found leaking
C970 -- 25v 470uF -- Replaced found lose
C398 -- 25v 1000uF -- Replaced looked funny tested fine replaced to be safe
C322 -- 16v 220uF -- Replaced looked funny tested fine replaced to be safe
C165 -- 50v 47uF -- Replaced looked funny tested fine replaced to be safe
C316 -- 25v 100uF --Replaced looked funny tested fine replaced to be safe --> replace with 35v 100uF

Then I plug it all back in to see what would now happen and goodbye fuse.

Tested -- C313  C514  D502 all good

on the attached sub board I've replaced

C512 -- 50v 1uF -- Replaced tested Bad
C511 -- 25v 100uF -- Replaced tested Bad --> replace with 35v 100uF
R513 -- 270k ohm  -- couldn't get any carbon so went for metal film

Plugged in and goodbye fuse

Checked for any errors and nothing.
Redid all dull points on the board and repeat my last two efforts.

not sure how I can go about testing the HOT Phillips BU2050DF it appears fine visually.

Anyone got any idea where i should look for the fuse blowing part? Before I either diminish the worlds supply of 4A 250v fuses or fork out and go nuts and replace everything I can see?

[mgb]

Fuse blowing and chirping. It's pretty likely the hot may be shorted.

Test the hot on diode scale with red lead on hot case and black lead to the metal frame.
Good hot will give a junction voltage reading.

Here's another similar post on this

http://forum.arcadecontrols.com/index.php?topic=79549.0

[madmanlxl]

Yep the HOT is in fact dead.

Well guess it's time to risk getting a replacement from the EvilBay. Guess this is going to take a few weeks/ months to get fixed (or I hit up Zax.com.au and pay $$$ for it). oh well.

Will update once I get some to test and make sure they are working before installing.

[mgb]

You should try www.therealbobroberts.net
Also keep in mind your Flyback may be damaged

[ed12]

madmanlxl
pm rickn here on this board
he is the mfg of the unit
and will know everything nessary.,i have yet to see the flyback go south
as a rule the horz output transistor,and the fet on the sub power board,
also u stated u recapped it
well there is 1 cap  on that board that setsup the slow start part of the board
it is replaced if i rem right from 1mf to 10 or 10 to 1 i would need to look at my 288 notes.

ed

[madmanlxl]

Well some good news. The worlds supply of 4amp 250v fuses are safe. Replaced the HOT and FET  (however it was replaced with a so called cross compatible part not sure if the nut bag just wanted to get rid of me or not).
So it starts and displays.....well displays white and what looks to be like a sync of v-hold issue. I'll get some free time later this week as I'm currently trying to plaster the room the cabinet is in as it'll be a arcade/studio room.

oh and the chassis was knocked over by a random dog (yes a random dog (beagle) walked into my shed to say hello?  ) and snapped a corner near the flyback. Took out a 7w1ohm ceramic resistor. replaced with a 5w1ohm, so far everything else seems OK after I cut the board cleanly and used wires and hot glue to fix it.

[madmanlxl]

Oops  Seems I forgot to put the cabinet together again correctly. Hadn't plugged the two sections together.

so it's now working again. Yay!



Thanks for the input. Damn cheap arse HOT.