Are Samyoung caps crap cant see bulging

[Clydeuk]

Re: Are Samyoung caps crap cant see bulging

I know why I'm not familiar with it. It's 240V AC here we don't use voltage doubler circuits. Before PFC came in it was just straight AC to the bridge and about 320V DC out of it.

[Clydeuk]

Re: Are Samyoung caps crap cant see bulging

I'm thinking you have a PTC thermistor in that primary as well, near the relay. If the relay isn't energising that will be carrying the supply to to bridge - hence why it will be slowly dropping as well as the thermistor's resistance increases.

[snake91876]

Re: Are Samyoung caps crap cant see bulging

if you go back to post number 12 and see the - sign that he circled if you go left and up you see those four spaced pins are those the bridge rectifiers, if so i tested the middle two to each other with meter on ac and have like 4volts.

[snake91876]

Re: Are Samyoung caps crap cant see bulging

Ok so i feel really stupid but i was testing the board hooked up being supplied with 120v. I was not turning tv on. I have 117v ac across the center terminals of the bridge rectifier steady. From the positive of the one capacitor to the negative of the other i have 315v dc. At the ballast output pins i have 315v dc. Would this indicate a good or bad powersupply considering the board is saying 380v dc.

[budm]

Re: Are Samyoung caps crap cant see bulging

That is good voltage, you will not get 380VDC form this voltage doubling circuit. The other circuit may have detected fault some where so it shutdown the power.

[snake91876]

Re: Are Samyoung caps crap cant see bulging

Could colowheel rpm shut down the circuit

[budm]

Re: Are Samyoung caps crap cant see bulging

I have no idea what this projector has as far as protection circuits are concern. Have to get the service manual or training manual to find out the details.

[cashkennedy]

Re: Are Samyoung caps crap cant see bulging

I concur that samyoung rarely fail, and lately manufacturers have been trusting them a lot for super thin LCD designs. But they are probably just marginally acceptable and I wouldn't be surprised if they start failing after 5-10 years.

What are the wires labeled as on the conectors leaving the power supply? Im not sure if you've tried testing for a pson signal, or standby voltages. Hard to know whether its shutting down for x reason before we even know if its shutting down

Welcome cyldeUK, Ive been seeing some pretty smart posts out of you. Are you friends with tom? or just happened upon the site recently ?

[snake91876]

Re: Are Samyoung caps crap cant see bulging

I have checked all voltages from powersupply and they seem to be correct, the lamp will go out and after about 2 to 3 seconds you hear the relays drop out. I can hear colorwheel running but i took it out and spun it and it spun till about the count of 10 looks good to me physically. I guess its in the main board or dmd board. If you replace the dmd how hard is it to line the dmd chip back up .

[tom66]

Re: Are Samyoung caps crap cant see bulging

I don't personally know Clydeuk, but I wouldn't mind meeting the chap. Any time he's in Leeds...