[BUILD] 1176LN Rev D DIY

[HMPS]

this trimmer is definitely bad.  i meant 1.99 kohms not hertz my mistake

measuring from center to left it stays 1.99 the other side stays at 2 ohms

doesn't move , i'll pick one up in the morning

 

[Echo North]

this trimmer is definitely bad.  i meant 1.99 kohms not hertz my mistake

measuring from center to left it stays 1.99 the other side stays at 2 ohms

doesn't move , i'll pick one up in the morning

Sounds like the wiper is stuck on one side.  Definitely a replace.

Good luck!

 

[john12ax7]

Could you guys tell me what fuse rating you are using? Anyone having toroidal turn-on problems with 250mA?

 

[Echo North]

You using a slow-blow?  It's gotta be a slow blow.

 

[john12ax7]

You using a slow-blow?  It's gotta be a slow blow.

Yes, the 250mA SB blew once, so not sure if it was just a random occorence. Gonna buy some more but right now have a 500mA SB with no issues. But with a 30VA transformer a 250mA seems more appropriate.

 

[Echo North]

You using a slow-blow?  It's gotta be a slow blow.

Yes, the 250mA SB blew once, so not sure if it was just a random occorence. Gonna buy some more but right now have a 500mA SB with no issues. But with a 30VA transformer a 250mA seems more appropriate.

If you just blew one 250mA slow blow, that can happen.  If you keep blowing them you might have an issue.

 

[john12ax7]

You using a slow-blow?  It's gotta be a slow blow.

Yes, the 250mA SB blew once, so not sure if it was just a random occorence. Gonna buy some more but right now have a 500mA SB with no issues. But with a 30VA transformer a 250mA seems more appropriate.

If you just blew one 250mA slow blow, that can happen.  If you keep blowing them you might have an issue.

Is 250mA SB the consensus "correct" choice then? It's the Hairball 30VA transformer.

 

[Echo North]

Ya for 120V users it's a good common value.

 

[john12ax7]

Ya for 120V users it's a good common value.

Cool, thanks.

 

[HMPS]

Ok tested and replaced trimmer.

I am seeing no meter movement or voltage variation on pad 7.

What should I check for?

 

[HMPS]

*note* the attack knob will vary the voltage of pad 7 to about -9.8

 

[andydiy]

Hi!

Mouser has no goods , Go there can buy？

Or there are other goods replacing?

Mouser Part #: 286-240-RC
Manufacturer Part #: 286-240-RC
Manufacturer: Xicon
Description: Metal Oxide Resistors 240ohms 5% Tol

 

[Echo North]

What is your DC V on either side of R35 (10K connected to the -10V rail), R60 (3.9K connected between that and ground), and on either outside terminal of R59.

Measure these 6 points compared to your CT.

 

[HMPS]

I see on the schematic where it says r35 is connected to the rail but I don't see it printed on the pcb.  Where can  I find it?

R60 -8 DCV, 0 DCV
R59 -8 DCV  other outside terminal 0 DCV

 

[HMPS]

r35 was covered by the other trimmer

r35 -9.6, -0.8
R60 -8 DCV, 0 DCV
R59 -8 DCV  other outside terminal 0 DCV

 

[Echo North]

r35 was covered by the other trimmer

r35 -9.6, -0.8
R60 -8 DCV, 0 DCV
R59 -8 DCV  other outside terminal 0 DCV

Your measurements don't make sense.  Do you mean R35 is -9.6, -8?  If so, there should be a much larger drop there.  It should be -9.X on one side and like -2V to -1V on the other side IIRC.  Either that or the one side of 60 and 59 are 0.8VDC

What are your DCV voltages on either side of R58?  It's on the ratio PCB.

Mike

 

[HMPS]

Ok,

We noticed we had 20 and 19 swapped in the wrong slot.  Putting them back voltage rail drops down to -8 VDC

When i remove 20 it goes back to -9.6 VDC so there is something on the ratio board that is off?

with 20 wire removed measurements are

r35  -9.6, -0.775
r60  -0.775, 0
r59 -0.775, -0.755, 0
rail 7  -0.45

 

[Echo North]

Ok,

We noticed we had 20 and 19 swapped in the wrong slot.  Putting them back voltage rail drops down to -8 VDC

When i remove 20 it goes back to -9.6 VDC so there is something on the ratio board that is off?

with 20 wire removed measurements are

r35  -9.6, -0.775
r60  -0.775, 0
r59 -0.775, -0.755, 0
rail 7  -0.45

I'm stumped.  You have a wiring issue or a component issue.  Sorry.

 

[Echo North]

Check the polarity and health of C21.  Check the value of R52 and R53. 

 

[HMPS]

reading 0 on C21, polarity is correct

R52  0, -0.028
R53 0, -0.028

with violet plugged in the reading is

0 on C21
R52 0, -0.019
R53 0, -0.019