Pentranic CH-888 19" CGA

[Liam]

Does anyone know anything about this chassis? It's labelled 21020888-01 CH-888 Rev: 0, and the part numbering is different from the schematics online for CH-288.

HOT is referred to as Q304.

The flyback is CH--9046 and is referred to as T302.

Chassis is ticking, and flyback seems to be unavailable, making the whole thing appear obsolete.

 

[gunblade]

if its a ch-888 then the HOT is Q302 2SC5250, Have you checked it for a short?

 

[Liam]

Thanks. In this monitor it's a BU2507DX. I took it out, and it appears to be short between base and emitter.

 

[gunblade]

well thats odd as the 2sc5250 does not have a damper diode whereas the bu2507dx does

 

[gunblade]

i have attached the schematic, hopefully this is your chassis

 

[Liam]

Great, the part numbers match, except HOT is Q304 here, and Q302 in the schematic. Maybe that's what the A in CH888A is for. Mine is just CH888.

 

[gunblade]

do all the other components match?
did the bu2507dx look like its the original transistor or do you think someone has replaced it at some point?

 

[Liam]

From what I can see, all other components match, and the component numbers on the board match, except for this one. The solder looked original.

 

[gunblade]

ok i just find it odd that a taiwan built chassis would use a phillips transistor which you only really find on european chassis plus the schematic does not show a damper diode built into the HOT

 

[Liam]

I think I'll change it for 2SC5250. If the HOT is the only change they made when revising the chassis, it might be alright. It's also cheaper and easier to find.