Re: ?problem with WH Purple Platypus

Posted by Kalimna on Feb 27, 2018; 11:36pm
URL: http://guitar-fx-layouts.238.s1.nabble.com/problem-with-WH-Purple-Platypus-tp41935p41941.html

Ok, here's a link to a couple of photo's :







The red tape is covering the LED resistor and also insulating the output jack socket from the enclosure - I drilled the hole a little close to the top.

And some voltage readings (yes, I realise there is a missing transistor in the photo's - it was replaced for the test). The 3 numbers following each testpoint are with both control pots fully off, halfway and fully on.

Supply - 8.94V, Q1 = 2N5087, Q2 = 2N5088

Q1 e - 1.9/2.6/2.6
Q1 b - 6.1/5.4/5.4
Q1 c - 6.7/6/6

Q2 e - 0.76/no change/no change
Q2 b - 1.4/nc/nc
Q2 c - 3.9/nc/nc

CD4049UBE (minimal or no change with pot settings)
1 - 5.7
2 - 2.4
3 - 2.4
4 - 1.1mV
5 - 5.7
6 - 0.5mV
7 - 5.7
8 - 0.2mV
9 - 5.2
10 - 1.4 mV
11 - 5.7
12 - 1.9mV
13 - 2.5mV
14 - 2.4
15 - 2.4
16 - 3mV

I thought the voltages around Q1/Q2 looked off, so I knifed the tracks again and had slightly different readings with collector at around 8V and gradually decreasing as the gain/vol pots turned fully on. base and emitter voltages changing in a simillar fashion.

Thoughts?

Adam