monitor jen shinn model 828h

[stackhouse]

I have this monitor on a 33" cabinet, and the problem is that the transistor (d5072) gets too hot, it can see the image of the game but after a while it doesnt work anymore and the horizontal transistors ( d5072 & bu2508af), both are broken.


Any idea what it may be?


Sorry my english. Im from Argentina

Thanks

[stackhouse]

Sorry, its a jen shinn monitor

[stackhouse]

sorry, its a jen shinn chassis

[grantspain]

do you have schematics?

[stackhouse]

no, I dont have it. But I asked on the jen shinn website and they say that the model 828h is for 28" CRT, but the videogame has been working 5 years with that chassis. I request the schematics but no reply yet.

[grantspain]

difficult to troubleshoot without seeing a schematic,i would start by replacing both the transistors that are blown and look for any damage to the high voltage caps on the horizontal output stage.

[stackhouse]

now, Im replaced both transistors but I have another problem, when I turn it on I heard the chassis is on but the CRT is still off,  and I cant heard the noise on the CRT everytime that the monitor get started. I dont know if I make myself clear. Thanks anyway.

[grantspain]

you are talking about the high voltage (ht),could be possible that the flyback transformer is dead considering its running a 33" tube and is meant for a 28"

yo intento in español
la problem es posiblemente la transformador de linea,no hay alta tension(HT)
normalmente una placa funcionando con un tubo mas grande que la correcto specifacacion peuder causa este transformador a morir después cada tiempo

yo creo es posible mejor a comprar un placa nueva directo de jen shinn porqué la transformador de linea este caro(pero no todo)

estoy aprendiendo español

[stackhouse]

Ok, but I've already change the flyback with the same one of another chassis, and still the same problem. Reading another posts, the neck doesnt glow when the monitor is powered up. Thats what I wanna say.

Thanks again

buena suerte aprendiendo espaañol

[grantspain]

check that your replacement transistors have insulation sheets if needed

[stackhouse]

I make it work  , it has a bad resistance. But know I think, when the chassis ( suitable 28") was brand new, it work fine for the 33" monitor, but now the chassis has been fixed several times and the years it has ,and now when I turn it on, after 10min. both horizontal transistors are broken. From now it must work on a 28" monitor.

 What do you think grantspain?

[grantspain]

i think there is another problem with the chassis,and i believe one of the high voltage polypropylene capacitors in the horizontal deflection circuit is defective thus blowing the transistors constantly
you will need to check each capacitor with a lcr meter to prove their operation is correct,if you have luck you will find one will be burnt or have a split by just looking