I have a 60v 5A cc cv PSU I got from chinabay.
I was playing with a SSTC that was running from it (yes yes very silly of me, I have a variac for that stuff)
Anyhow now the relays in the PSU don’t switch. I'm still in the process of removing the boards, so pics soon.
The op-amps I could get a probe to and the pass transistors all seem to be ok. The most obvious issue is the relays not switching to different secondary as the range voltage is adjusted or if the current demand goes up.
So while I am looking at the relay driving setup is there anything else I should check while I'm in there?
I had just had the TC throwing a good bit of plasma from 30v input and turned the voltage down to 0v to make a change on the topload. When I turned it back up the psu got stuck in the 5v-13v range. Its low on current too, only puts out about 1.5a. There is a telling lack of the relays clicking sound as the voltage is adjusted through the range.
I'd say the TC was sending a lot too much power to the coils in the relays and either melted the wire on the coils or blew the relay coil transistors, maybe an op amp or something behind that. Induced Voltage on the coils would have been minimal while the relays are magnetised, but when they switch off they probably turn into great wireless power receivers... Even a nail can spew a few inches of plasma stream near this particular coil, It lights large fluros a meter away. So anybody’s guess what kind of voltages the relay coils could have seen, but well into the corona discharge is setting stuff on fire ranges I'd say.
In hindsight I probably should have at least used a longer lead to power the approx 30kv Tesla coil. Running it 8 inches from the psu, with the psu on the shelf at topload height was probably asking for a repair job.... This is why I have a variac...
I was playing with a SSTC that was running from it (yes yes very silly of me, I have a variac for that stuff)
Anyhow now the relays in the PSU don’t switch. I'm still in the process of removing the boards, so pics soon.
The op-amps I could get a probe to and the pass transistors all seem to be ok. The most obvious issue is the relays not switching to different secondary as the range voltage is adjusted or if the current demand goes up.
So while I am looking at the relay driving setup is there anything else I should check while I'm in there?
I had just had the TC throwing a good bit of plasma from 30v input and turned the voltage down to 0v to make a change on the topload. When I turned it back up the psu got stuck in the 5v-13v range. Its low on current too, only puts out about 1.5a. There is a telling lack of the relays clicking sound as the voltage is adjusted through the range.
I'd say the TC was sending a lot too much power to the coils in the relays and either melted the wire on the coils or blew the relay coil transistors, maybe an op amp or something behind that. Induced Voltage on the coils would have been minimal while the relays are magnetised, but when they switch off they probably turn into great wireless power receivers... Even a nail can spew a few inches of plasma stream near this particular coil, It lights large fluros a meter away. So anybody’s guess what kind of voltages the relay coils could have seen, but well into the corona discharge is setting stuff on fire ranges I'd say.
In hindsight I probably should have at least used a longer lead to power the approx 30kv Tesla coil. Running it 8 inches from the psu, with the psu on the shelf at topload height was probably asking for a repair job.... This is why I have a variac...