Speedball problems

zlobby · 2878

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Offline zlobby

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on: November 28, 2011, 01:31:07 PM
I just completed installing my speedball and the first thing i noticed is that not all of the LEDs on the PCBs light up.

When i went to go test my voltages, these are the readings i got with many of them off.  I stopped at 20, because there was a small spark and a loud pop.  Im not sure if i shorted something a resistor with my probe.


Terminal Voltage (VDC)
1 75
2 82
3 0
4 82
5 69
6 0
7 72
8 0
9 62
10 0
11 0
12 0
13 79
14 0
15 132
19 71
20 0



Offline Laudanum

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Reply #1 on: November 28, 2011, 02:14:44 PM
Post the expected voltages as per the manual next to your measured values.  It makes it easier for someone to help you because they wont have to refer to the manual.  Also, may want to post resistance measurements and expected values.  You dont need to turn it on for that.

Desmond G.


Offline Jim R.

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Reply #2 on: November 28, 2011, 03:13:45 PM
Also check to make doubly sure that you installed the right transistors on the appropriate board -- they aren't all the same, and one type goes on the driver tube boards, and another on the plate loads for the output tube board.  This seems to be the most frequent cause of no or partial lighting of the LEDS.

-- Jim

Jim Rebman -- recovering audiophile

Equitech balanced power; uRendu, USB processor -> Musette DAC -> 5670 tube buffer -> Finale Audio F138 FFX -> Cain and Cain Abbys near-field).

s.e.x. 2.1 under construction.  Want list: Stereomour II

All ICs homemade (speaker and power next)


Offline Grainger49

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Reply #3 on: November 29, 2011, 03:23:34 AM
(hanging head in shame)  Yes, even an experienced kit and scratch builder can fall into this trap.

Also check to make doubly sure that you installed the right transistors on the appropriate board -- they aren't all the same, and one type goes on the driver tube boards, and another on the plate loads for the output tube board.  This seems to be the most frequent cause of no or partial lighting of the LEDS.

-- Jim