Mark goes at it again... just bought a PL700/II!

[MarkWComer]

How about the pico fuses?

Left and right picos read good... Zero ohm resistors read good

 

[Gepetto]

Remember nothing is shared on the G1 so if your negative regulator is not working that is where the troubleshooting starts

 

[MarkWComer]

Remember nothing is shared on the G1 so if your negative regulator is not working that is where the troubleshooting starts

VR50 is a conductor, not a semiconductor!
I wonder what made it fail...

Will get on Mouser or DigiKey in the morning...

 

[laatsch55]

Breathing on it...

 

[Gepetto]

VR50 is a conductor, not a semiconductor!
I wonder what made it fail...

Will get on Mouser or DigiKey in the morning...

PM me your address and I will mail you one Mark.

 

[MarkWComer]

D50 shows 11Ω in both directions, D53 looks good, too

 

[Gepetto]

VR50 is a conductor, not a semiconductor!
I wonder what made it fail...

Will get on Mouser or DigiKey in the morning...

Had it failed open you would have gotten ~19.3V

 

[MarkWComer]

Breathing on it...

Yeah, that does it sometimes. I should brush my teeth, but since the quarantine, why bother?

 

[MarkWComer]

I should add that Q50 checks OK, no problem with that.

 

[MarkWComer]

On the plus side, reviewed the video clips and they look great.
Getting the knack of this camera.

 

[jbeckva]

Dunno when your vid's private.. but if there are backplanes involved then pico fuses?

 

[MarkWComer]

Dunno when your vid's private.. but if there are backplanes involved then pico fuses?

Yes, found it. It is one of the picos. SHIT! Have to pull a backplane...

 

[MarkWComer]

The saga continues...

And continues further:

 

[FredR]

Great stuff Mark! On behalf of the community, THANKS!

 

[silver_face]

Yes, found it. It is one of the picos. SHIT! Have to pull a backplane...

Had to do pull backplanes on a PL 400, (pico blew) I populated a transistor where it did not belong on the control board.
Great vid's

 

[MarkWComer]

Had to do pull backplanes on a PL 400, (pico blew) I populated a transistor where it did not belong on the control board.
Great vid's

Thank you!

I think that fusing scheme has been changed in the rev. C backplanes from what I can see in the pictures.

 

[silver_face]

Also on that PL 400 that I did, I had a probe slip and took out a zenor diode and a transistor.
Your vid's will help me do my Pl 700II. I already replaced the meters with White Oak meters , you gonna love Em...

 

[silver_face]

We are not gonna be the only ones to show the world what not to do by doing it....

 

[MarkWComer]

We are not gonna be the only ones to show the world what not to do by doing it....

I’m still not 100% sure what I did, but pretty sure I hit the heat sink, not the transistor pin. The test point is so close to that sink that it’s easy to make that hit. I was told that I wasn’t the first to do this, so it must be a pretty common occurrence.

 

[MarkWComer]

So... funny thing...
YouTube slaps a copyright bust on me for playing music in the background during my PL400 vids, but not for lifting the Three Stooges opening theme on these two latest uploads. I clipped from a couple Hollywood releases, too- but no bust from those, either.

Stupid, right?