January 14, 20215 yr Author On both the + & - output of the unit is a chunky resistor. Both look a bit brown but both measure at 5.6 Ohm. It holds with me thinking it died as the output was shorted.
January 14, 20215 yr Author The two ICs in the foreground, in front of the regulator are 7612 op amps.
January 14, 20215 yr something's certainly pulling it down. Maybe try cutting the odd track to narrow it down?
January 14, 20215 yr Google found. https://www.radwell.co.uk/en-GB/Buy/CARLO GAVAZZI/CARLO GAVAZZI/FPD1901220 But its expensive. They offer to repair one for £177.
January 14, 20215 yr Author Just now, Temp said: Google found. https://www.radwell.co.uk/en-GB/Buy/CARLO GAVAZZI/CARLO GAVAZZI/FPD1901220 But its expensive. They offer to repair one for £177. Yep, I know Radwell and am aware of that option.
January 15, 20215 yr Author 3 hours ago, dpmiller said: something's certainly pulling it down. Maybe try cutting the odd track to narrow it down? In this photo, top right, at the back is the green supply LED. That's now coming on whereas it wasn't before. That is it's coming in even with these low DC voltages. The vertical boards to the right are essentially the channel generator I think and the right hand side, around the regulator crates the 8.2vdc that goes down pin 6. The other wire for the 2 wire comms is pin 3. In my application it's just supply to A1/A2 and then 2 wires from 3 & 6. I should be measuring I think 8.2vdc across 3 & 6. I'm measuring 1vdc only. (Pins 2 & 4 not used).
January 15, 20215 yr Author Is perhaps the 0-15v transformer not a high enough voltage to start with? Then: As I read it there's a minimum voltage differential of 3V needed. I've 5Vdc out of the bridge rectifier and R1/R2 are set up to give Vout as over 12V. So a circa 7V differential. (I have btw the 317T not 317N). Thinking to sling in a 0-24V trannie and see what gives.
January 15, 20215 yr If it 22VAC off load and you're only seeing 5VDC out of the bridge, there's a short somewhere IMHO. I'd be removing the supply from each of the op-amps and from the two cards, to try and pinpoint it.
January 15, 20215 yr 7 hours ago, Onoff said: As I read it there's a minimum voltage differential of 3V needed. I've 5Vdc out of the bridge rectifier and R1/R2 are set up to give Vout as over 12V. So a circa 7V differential. Typo? You've got a -7V differential. eg If Vout is designed to be 12V then Vin must be >15V.
January 15, 20215 yr Probably not this but in one image it looks like a resistor lead might be touching the heatsink tab of the 317. The tab is connected to the Output of the 317 regulator inside it so accidental electrical connections should be avoided. (aside: You might also be able to use the tab as a convenient place to measure Vout.).
Create an account or sign in to comment