Re: Does anyone have the schematic of a Tagan BZ700 PSU?

Thanks for the reply. I'll check the main cap, but I'd really like to dig deeper into the circuit. I'm a pro - semi-retired now - in electronics and not wanting to trash this PSU isn't just a matter of money.

Re: Why does my Seasonic SSR-500GB3 whine??

A stethoscope is great for locating the source of a noise. Even the cheapest ones will do. Just remove the chestpiece and point the open end of the tube around. I've been using the technique for 50+ years in my work.

Does anyone happen to have a circuit diagram (schematic) of a Tagan BZ700 PSU that they can share? I searched but had no luck.

One of two MOSFETs in the PFC circuit blew about 5 years ago. Not having the exact type, I replaced both with a similar type and it's been running fine, 10-16 hours a day every day, until one blew again last month. On both occasions, the transistor blew when there was a severe power fluctuation and the UPS kicked in and out in rapid succession.

The first time it happened, the PSU simply became inoperative. This time it took out the fuse in...

Re: BenQ G2420HD cannot stay lit up

Simply disconnecting the RTD2482RD pin 102 would do that as R114 will then permanently pull up the ENA line. But then the monitor will stay lit up even when the rest of the circuit goes into standby.

I suppose I can live with that if all else fails. I could also design and add a separate sync detector and use that to turn the backlight on and off. Thing is, I don't like leaving a problem unsolved. If this were a known problem that sometimes happens with this display controller chip (the RTD2482RD, not the inverter controller), I'd...

Re: BenQ G2420HD cannot stay lit up


I agree, but I can't find spare CCFLs. In fact, I have not replaced the broken CCFL at all. When I said that I solved the problem, it was a simplification. I have ordered LED replacements from China but they'll take at least a month to arrive.

I tested the monitor with only two CCFLs installed. Only one of the four CCFL outputs has a load sense feedback to the inverter control and I made sure that one CCFL was in that socket.

As it is the Enable signal from logic board that keeps turning the inverter off,...

Re: BenQ G2420HD cannot stay lit up

Thanks for your interest. I thought no one was going to reply.

I already downloaded the service manual a few days ago but while it's quite detailed about some aspects, it's sketchy about others.

That thread of yours is quite long and will take some time to go through.

It's getting close to midnight here now and I have a heavy day tomorrow. So it may be some time before I can pursue this further and have something to report.

I have a BenQ G2420HD monitor that was damaged during transportation. Two of the four CCFL tubes were broken and I've solved that problem but it still has a fault. These are the symptoms:

1. When switched on, it lights up and presents a normal display FOR ONE SECOND, then goes dark for 3 seconds, lights up again for one second and then goes dark permanently. Power cycling makes it repeat the same behavior over and over.

2. It detects the video and sync inputs. The pilot light stays green as long as there's a signal input (even when the screen goes dark by itself as described)...

Re: New Members - please post your introductions here

Hi, everyone.
Electronics is both my profession and my hobby. I've seen BadCaps mentioned here and there over the years but never got around to joining it until now. I've just joined to post about a problem (I can't be the only one to do that) but will probably stick around for a long time.