VU2 stereo VU buffer kit Build thread

[AALF]

Thank you for your help.
Still cannot get it working, so going to order new prebuilt board.
That way i can compare and figure things out.
Thank you and Merry Christmas!
AALF

[Joe Malone]

Thank you for your help.
Still cannot get it working, so going to order new prebuilt board.
That way i can compare and figure things out.
Thank you and Merry Christmas!
AALF

First can you measure the voltages on the 8 x TL072 pins measured from Gnd and put them up so we can see if the buffer is working or not.

I also wonder if the 12v power supply designed for led lamp is smooth enough for running the buffer. Usually they have minimum smoothing so have high frequency noise all over the output

[AALF]

Ok
Replaced 12v led power with regular 12v 2A (new) plug-in power pack.
Measured voltages from Vcc-. Vcc+ 12v. All others pins are the same at 6.23v dc. Regardless of hooked input or not.
Think the chip is Kaput.

[Joe Malone]

Ok
Replaced 12v led power with regular 12v 2A (new) plug-in power pack.
Measured voltages from Vcc-. Vcc+ 12v. All others pins are the same at 6.23v dc. Regardless of hooked input or not.
Think the chip is Kaput.

The TL072 should have 12vdc on pin 8 and 0v on pin 4. All other pins should be roughly 6vdc so IC seems to be working ok. Because you are measuring dc you will not see the vac audio signal when connected.

Do you have a better input device as something very simple is wrong. CD player with RCA outputs etc.

What does the soldering under the pcb look like ? Do you have a clear photo of it.

The meter needles bounce upwards for a second when powered up?

[AALF]

The needles do bounce on power up.
And I think your right about the solder job. Been thinking about it these past few days.
Looks good but doesn't mean I missed one or two.
Going to check the RCA jacks also.
Time to retire the old Hako iron I think (20+ years). Bought a weller we-1010 last year, still in the box.
Time to give it a go. With the holidays coming up it might be a few days before I get back to you.

Thanks and Merry Xmas
AALF