News: Trouble logging in? Log in from the login page.
August 18, 2019, 06:16:39 AM

Author Topic: Reduction build completed, incorrect voltages [SOLVED]  (Read 557 times)

0 Members and 1 Guest are viewing this topic.

Offline cjohannsen

  • Newbie
  • *
  • Posts: 9
Reduction build completed, incorrect voltages [SOLVED]
« on: June 24, 2017, 01:08:15 PM »
I've completed my build of the Reduction, and it is powering on but the voltage measurements are definitely incorrect.

I performed the Power Transformer Test during assembly and the values matched the manual.

I finished the assembly and tested all the resistances.  Everything looks correct except for terminal 31, which I'm reading as ranging near 63-67k Ohm, and the manual indicates that this should be an OL.  This seems like an error in the manual, since the connections mirror terminal 2, which is indicated in the manual as ranging (which matches my measurements)

I measured every terminal and recorded the DC voltage:
Terminal   DC Voltage    Expected DC Voltage
1           0               0
2             0.25           70-90
3             0          0
4             0.25          145-155
5             0          0
6             0          0
7             0.25          70-90
8             0          0
9             0          0
10             0          0
11             0          0
12             0          0
13             0.25          70-90
14             0.25          70-90
15             0.25          70-90
16             0          0
17             0          0
18              0.25          70-90
19             0.25          70-90
20             0.25          70-90
21             0          0
22             0          0
23             0          0
24             0          0
25             0          0
26             0.25          70-90
27             0          0
28             0          0
29             0.25          145-155
30             0          0
31             0.25          70-90
32             0          0
33             6.09          6
34             0          0
35             0          0
36             0          0
37             6.07          6
38             10.53       10-11
39             3.94          4-5
40             0          0
41             3.95          4-5
42             10.63       10-11
43             0          0
44             0.25          180
45             0          0
46             0          0
47             0          0
48             0          0
49             0          0
50             0.25          165
51             0.25          165
52             0.25          180
53             0.25          180
54             0          0
55             0          0
56             0.25          145-155
57             0.25          145-155
58             0          0
59             0.25          165
60             0.25          165
61             0          0
62             0          0

I also measured the tube socket terminals for reference, but I don't know what values to expect:
A1   0.11
A2   0
A3   0.76
A4   6.08
A5   0
A6   0.16
A7   0
A8   1.06
A9   0
B1   0.18
B2   0
B3   0.82
B4   6.08
B5   0
B6   0.19
B7   0
B8   0.81
B9   0

All of the terminals that measured 0.25 VDC started out in the millivolt range, and gradually increased to this value, and continue to increase beyond at a very, very slow rate.

I re-measured the power transformer output with the unit fully assembled, and now I am getting an strange measurement:
PS2 measures 121.5 VAC
PS5 measures 9.2 VAC
PS7 measures 0.97 VAC (expected this to be around 135 VAC)

Should I still be measuring 135 VAC across PS 6-7? 

I've attached pictures of the assembled unit for reference.

Are there any obvious errors that I have made?  Additional measurements I can take to help narrow down the problem?

Thanks in advance,
Cory Johannsen
« Last Edit: June 24, 2017, 09:24:31 PM by cjohannsen »

Offline Chris65

  • Sr. Member
  • ****
  • Posts: 331
Re: Reduction build completed, incorrect voltages
« Reply #1 on: June 24, 2017, 02:24:49 PM »
PS7 measures 0.97 VAC (expected this to be around 135 VAC)
Should I still be measuring 135 VAC across PS 6-7?

Hi Cory. Looking at your first photo, from what I can tell it appears that the wire from the transformer winding has become detached from transformer terminal 7. This would certainly explain the lack of voltage.

I finished the assembly and tested all the resistances.  Everything looks correct except for terminal 31, which I'm reading as ranging near 63-67k Ohm, and the manual indicates that this should be an OL.  This seems like an error in the manual, since the connections mirror terminal 2, which is indicated in the manual as ranging (which matches my measurements)

Yes, this is an error in the Manual. Terminal 31 should be * (resistance value will vary)

Offline cjohannsen

  • Newbie
  • *
  • Posts: 9
Re: Reduction build completed, incorrect voltages
« Reply #2 on: June 24, 2017, 09:24:03 PM »
That was it!

I soldered the transformer wire back to the output tab, and now it makes sweet, beautiful music!

Thanks so much for the help, I NEVER would have spotted that!

Cory

Offline Chris65

  • Sr. Member
  • ****
  • Posts: 331
Re: Reduction build completed, incorrect voltages [SOLVED]
« Reply #3 on: June 25, 2017, 02:38:35 AM »
Glad to help ;D.