What are the voltages at the secondaries 20v?
3D "AIR" EQ - "Night EQ" PCB's Complete!
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djmiggymigz
Well-known member
Okay yeah thats very similar to mine except I have 2 4700 uF caps rather than four 1000's.
Yes the secondaries (in refrence to the center tap) are both outputting 20.9 VAC.
Just wire it like the diagram trace the voltages down the line until it goes low on the neg regulator. you may have a shoddy part are solder joint...
Then your transformers working.
djmiggymigz
Well-known member
okay will do. Like I said, Testing continuity I just shorted a blew up a diode connection! Gonna be more careful this time.
Since the positive side seems to be fine is it okay to compare the volt readings from the positive side to what Im getting on the negative side? should they be more or less similar going down the path?
Since the positive side seems to be fine is it okay to compare the volt readings from the positive side to what Im getting on the negative side? should they be more or less similar going down the path?
djmiggymigz
Well-known member
So this circuit is using a 5k trimmer for VDC calibration out of the regs. Should I have continuity between the adj pin of the regs and all three pins of the trimmer(s)?? On the positive side I do but, on the negative side I only have continuity to 2 pins of the trimmer. (the pin without continuity is on the side with the trim pot)
djmiggymigz
Well-known member
Okay we've succesfully made it back to my original point of confusion. SO:
All voltages look good and are mirrored along the path. Now when measuring the Reg Input terminal. When refrencing with the black probe on the main AC Ground, I'm reading +- 29.xxx VDC respectively. However, if I reference that same measurement to the DC Ground I read +2.9xx VDC at the input of both regs.
Now when testing at the DC Output terminals: When referenced to the main AC Ground Im reading -26.3xx and +23.xxx VDC. When taking that same measurement in reference to the DC Output Ground terminal (as well as the PE pad which has continuity to the DC G terminal) both side go crazy and my meter is jumping all over the place.?? Never settling on a reading for either side. Ideas??
All voltages look good and are mirrored along the path. Now when measuring the Reg Input terminal. When refrencing with the black probe on the main AC Ground, I'm reading +- 29.xxx VDC respectively. However, if I reference that same measurement to the DC Ground I read +2.9xx VDC at the input of both regs.
Now when testing at the DC Output terminals: When referenced to the main AC Ground Im reading -26.3xx and +23.xxx VDC. When taking that same measurement in reference to the DC Output Ground terminal (as well as the PE pad which has continuity to the DC G terminal) both side go crazy and my meter is jumping all over the place.?? Never settling on a reading for either side. Ideas??
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scott2000
Well-known member
What is a PE pad?
djmiggymigz
Well-known member
"Protective Earth" I believe from what a google unveiled. Its a blank pad next to the DC Output terminals that has continuity to the DC Ground.
scott2000
Well-known member
Hmmm.. it almost seems like you are getting readings you should but I won't lie, I'm having a hard time understanding some of the info...
I mean, you set your meter to dc, if you put the positive lead on a negative dc point and the negative lead to a ground...ground is ground...chassis...whatever...you should read a negative dc voltage...
If you stick your positive lead on a positive dc point, and the negative lead on ground, you should get a positive dc measurement....
djmiggymigz
Well-known member
Yeah sorry, I'm really confused by what is seemingly an issue. This is my first time building and dealing with a PSU.
So: Ive checked all the components. I have good AC Voltage getting to the regulator (317/337) inputs. This specific board is calling for +-18 VDC at the DC Output terminals (+, G, -). When trying to calibrate the V+ and V- trimmers to get the right readings (here's where the issue comes into play), I'm getting vastly different DCV readings on my multimeter depending on where I have the negative lead of the multimeter. Measuring now and logging as I do (with the DC Outputs disconnected so PSU Isolated):
With negative probe on main AC Ground Terminal:
DC Output + Terminal = +18.08 VDC
DC Output - Terminal = -18.03 VDC
DC Ground Terminal = +16.54 VDC
With negative probe on DC Output Ground Terminal:
DC Output + Terminal = - 9.9 VDC VDC
DC Output - Terminal = -38.62 VDC
Those massively different readings are whats confusing me. I didn't move the trim pots, nada, just changed the point at which the negative MM probe was connected.
scott2000
Well-known member
I've been confused by much less. Just be careful
I'm assuming you mean DC voltage? Should have been rectified to DC before the regulators?
How is your transformer wired to the board? Like the image Bobby Baird posted?
getting late here...
found this somewhere in another thread..
Maybe useful..... also...guess you need to verify you used isolators when you mounted your regulators to the heatsinks.....
keep at it....
Sorry whoops...lol
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djmiggymigz
Well-known member
Thanks for saying that,, figuring things like this out for the first time is no easy feat without resources like this community!!
Yeah you’re probably right, that was probably supposed to say DC tho I’ll double check that tomorrow.
Yes transformer connection is identical to that pic. Only thing not shown in that picture is the AC Ground terminal right next to terminal 4. That I have connected to the toroid screw where the IC Inlet ground is also connected
Yeah you’re probably right, that was probably supposed to say DC tho I’ll double check that tomorrow.
Yes transformer connection is identical to that pic. Only thing not shown in that picture is the AC Ground terminal right next to terminal 4. That I have connected to the toroid screw where the IC Inlet ground is also connected
peterc
Well-known member
Are your Grounds connected together? turn it all off and check the continuity between the AC and DC Grounds.
djmiggymigz
Well-known member
Hmmmm this could be it. As I was poking around checking for continuity all over the place yesterday, DC ground was not connected to AC Ground!
There’s the PE pad that’s right next to the DC terminals that is connected to the AC ground. Can I just run a wire from that to the star ground on the toroid screw?
There’s the PE pad that’s right next to the DC terminals that is connected to the AC ground. Can I just run a wire from that to the star ground on the toroid screw?
scott2000
Well-known member
I probably wouldn't... Without knowing anything, I'd say something else is goofy somewhere..
That power transformer doesn't give any indicators/marks of phasing ?
Maybe a full shot of your power supply board will give clues....
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djmiggymigz
Well-known member
I posted a full pic here a bit back. Let me know if you can't open/see that and I'll just repost it.
Would connecting the AC/DC Grounds present any sort of danger? It would be easy enough to run a quick jumper to the star ground and see what it does. Again, first time working with PSU and dealing with mains so I'm not sure if that would be dangerous. Had a very unhelpful person on reddit scold me (i posted there as well) for not knowing what I'm doing, saying I could die and whatnot lol. I'd rather not
scott2000
Well-known member
I just see tidbits of sections...
When troubleshooting, it's usually best to get things working as they should. Judging from other pictures I've seen, that doesn't appear to be something done the way you're describing. Just saying I wouldn't.
djmiggymigz
Well-known member
Well thru troubleshooting the entire PSU signal flow, the only thing that stands out as wrong/not working is the fact that the AC ground did not have continuity to the AC Ground.
djmiggymigz
Well-known member
Update: Added a wire going from the DC Ground to the star ground at the toroid screw. Nothing blew up 
D) and I was able to easily calibrate both +- DCV to +- 16 DCV (as peter recommended)!!! That seems to have solved the problem. Tested across my L/R PCB's. Getting proper voltage at the DC inputs, as well as the respective IC pins!! Problem solved!! Big thanks to everyone that tapped in with their two sense. Y'all are awesome.
On to the next problem!! Left it on for a second with both channels engaged and a resistor on the L channel burned up (small *pop* sound and smoke. It's a 22 ohm resistor labelled "RPSU" right around the DC Input. There's I 4 of these identical resistors per channel. Going to make sure there's no shorts on the PCB. Luckily I have a ton of the value to pick from. Probably will measure the ohms of the other three and find one that closely matches what the others are sitting at.
Any ideas why that may have happened? Short/bad solder connection? I cleaned the PCB's real good. Probably just need to give it a good inspection.
Overall, major win tho!! I'm so stoked rn hahah. Thanks again y'all.
D) and I was able to easily calibrate both +- DCV to +- 16 DCV (as peter recommended)!!! That seems to have solved the problem. Tested across my L/R PCB's. Getting proper voltage at the DC inputs, as well as the respective IC pins!! Problem solved!! Big thanks to everyone that tapped in with their two sense. Y'all are awesome.On to the next problem!! Left it on for a second with both channels engaged and a resistor on the L channel burned up (small *pop* sound and smoke. It's a 22 ohm resistor labelled "RPSU" right around the DC Input. There's I 4 of these identical resistors per channel. Going to make sure there's no shorts on the PCB. Luckily I have a ton of the value to pick from. Probably will measure the ohms of the other three and find one that closely matches what the others are sitting at.
Any ideas why that may have happened? Short/bad solder connection? I cleaned the PCB's real good. Probably just need to give it a good inspection.
Overall, major win tho!! I'm so stoked rn hahah. Thanks again y'all.
