Screwed up my Crack upgrade

flyfisher55 · 5656

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Offline flyfisher55

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Reply #30 on: February 16, 2019, 10:39:23 AM
Everything that I in error labeled as "0" is in fact 0.L m ohms. My apologies.



Offline Paul Birkeland

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Reply #31 on: February 16, 2019, 10:43:33 AM
I would recheck Q1B on the big board.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline flyfisher55

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Reply #32 on: February 16, 2019, 11:04:11 AM
I need steady hands, someone to teach me ohms law and a drink!
ok don't ask me where I got those previous numbers but this is what I'm seeing now .08 L+R, L+C .09, R+C 0 all M ohms



Offline Paul Birkeland

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Reply #33 on: February 16, 2019, 11:40:01 AM
I need steady hands, someone to teach me ohms law and a drink!
ok don't ask me where I got those previous numbers but this is what I'm seeing now .08 L+R, L+C .09, R+C 0 all M ohms
Is R+C 0, or OL?

If it's 0, then that's a dead transistor.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline flyfisher55

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Reply #34 on: February 16, 2019, 12:51:27 PM
I'm seeing zero



Offline Paul Birkeland

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Reply #35 on: February 16, 2019, 01:14:36 PM
She's toast! (I'd replace them both on that side)

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline flyfisher55

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Reply #36 on: February 16, 2019, 01:40:55 PM
what about the others and my wacky readings? These parts are cents ... Not better off just swapping all parts in question?



Offline flyfisher55

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Reply #37 on: February 16, 2019, 01:56:01 PM
also the issue with small board still not working after having removed the large. Do we need to replace parts there?



Offline Paul Birkeland

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Reply #38 on: February 17, 2019, 08:47:50 AM
You can do the same readings again on the small PC board to check for shorts.

Again, it's low impedance values between any pair of transistor legs that mean a problem.  If there's an "M" in the reading or it says "OL", those are OK readings.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline flyfisher55

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Reply #39 on: February 27, 2019, 05:08:34 AM
Sorry it took me awhile...

these are the transistor readings from small board
Q1A- L+C 32.23 m ohms
        L+R 0.L m ohms
        C+R 37.78 m ohms

Q2A- L+C 0.L m ohms
        L+R 28.10 m ohms
        C+R 16.85 m ohms

Q1B- L+C 33.0 m ohms
        L+R 0.L m ohms
        C+R 38.25 m ohms

Q2B-L+C 11.36 m ohms
       L+R 000.7 m ohms
       C+R 11.52 m ohms



Offline Paul Birkeland

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Reply #40 on: February 27, 2019, 05:16:20 AM
Q2B looks to have a short.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline flyfisher55

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Reply #41 on: February 27, 2019, 11:19:08 AM
Should I order defective parts from an electronics part shop online or through Bottlehead?



Offline Paul Birkeland

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Reply #42 on: February 27, 2019, 03:02:11 PM
Whichever is easier.  There are a decent number of local electronics shops that will carry the NTE line of semiconductors.  The NTE123A and NTE198 are the equivalent transistors that go on the larger PC board while NTE159 and NTE39 go on the smaller board.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline flyfisher55

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Reply #43 on: May 03, 2019, 09:30:42 AM
Hello Paul, I'm back to trying to restore my crack. I ordered parts online and replaced the parts in question. Here are my results on large board OA- OL
                 OB- OL
                 G- 0
                 B+- OL
  02B heatsink hot

LED nearest outside rim on B+ side lit
Both LED's on left side of small board lit
One LED at vaccuum tube base lit
All other LED'S are out.



Offline flyfisher55

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Reply #44 on: May 03, 2019, 09:41:32 AM
I'm presuming the problem has to be traced so I removed large board.