Bottlehead Forum

Bottlehead Kits => Legacy Kit Products => Reduction => Topic started by: cuplinks on December 29, 2019, 10:49:00 PM

Title: Blown resistors at 53-60 and 51-57 [resolved]
Post by: cuplinks on December 29, 2019, 10:49:00 PM

Hello, I just received my Reduction kit in the mail this morning and have spent all afternoon following the manual. Lots of fun!

I noticed a error in the resistance check at 47 similar to this thread https://forum.bottlehead.com/index.php?topic=11818.0

So, assumed all was ok and moved on. Powered on and tubes lit up (although the right one seemed brighter). Powered down and flipped the kit to see some smoke and those two 1KOhm-1W resistors between terminals 53-60 and 51-57 browned out.

Any ideas on how to diagnose and/or fix the problem?

I had some problems with the diodes between terminals 44 through to 47 as I think I soldered something before I was supposed to and had reflow and get the new leads through which was a bit awkward.

I am in Australia and my mains voltage check was 234.5 volts so added the wire between terminals 14 and 16 on the transformer.

I haven't done the final voltage checks yet, but the secondary tests were all within range.

Cheers,

James

Title: Re: Blown resistors at 53-60 and 51-57
Post by: Paul Birkeland on December 30, 2019, 05:12:48 AM

Could you post some photos of your build and a complete rundown on resistances?  You definitely don't want to turn it back on for now.

-PB

Title: Re: Blown resistors at 53-60 and 51-57
Post by: cuplinks on January 01, 2020, 03:37:46 PM

Hi Paul,

Reading and pictures as requested;

1 - 0.3 Ohm
2 - 17.91 KOhm
3 - OL
4 - 0.3 Ohm
5 - OL
6 - OL
7 - 17.81 KOhm
8 - 0.3 Ohm
9 - 0.3 Ohm
10 - 0.473 MOhm
11 - 0.3 Ohm
12 - OL
13 - 103.2 KOhm
14 - 92.5 KOhm
15 - 17.81 KOhm
16 - 0.3 Ohm
17 - 0.3 Ohm
18 - 17.97 KOhm
19 - 92.6 KOhm
20 - 103.4 KOhm
21 - OL
22 - 0.3 Ohm
23 - 0.472 MOhm
24 - 0.3 Ohm
25 - 0.3 Ohm
26 - 17.97 KOhm
27 - 0.998 MOhm
28 - OL
29 - 0.3 Ohm
30 - OL
31 - 17.8 KOhm
32 - 0.3 Ohm
33 - 3.4 Ohm (tube in)
34 - 0.3 Ohm
35 - 0.3 Ohm
36 - 0.3 Ohm
37 - 3.4 Ohm (tube in)
38 - 7.4 Ohm
39 - 3.77 KOhm
40 - 0.3 Ohm
41 - 3.76 KOhm
42 - 7.5 Ohm
43 - 0.3 Ohm
44 - 4.63 MOhm
45 - 4.63 MOhm
46 - OL
47 - 1.96 KOhm
48 - 0.3 Ohm
49 - 0.3 Ohm
50 - 0.986 KOhm
51 - 0.986 KOhm
52 - 1.962 KOhm
53 - 1.962 KOhm
54 - 0.3 Ohm
55 - 0.3 Ohm
56 - 0.3 Ohm
57 - 0.3 Ohm
58 - 0.3 Ohm
59 - 0.985 KOhm
60 - 0.985 KOhm
61 - 0.3 Ohm
62 - 0.3 Ohm

Title: Re: Blown resistors at 53-60 and 51-57
Post by: Paul Birkeland on January 01, 2020, 05:49:35 PM

You have a miswire at terminal 4 which has connected the output of the power supply to ground.

Title: Re: Blown resistors at 53-60 and 51-57
Post by: cuplinks on January 01, 2020, 07:13:59 PM

Thanks Paul,

All good.

Cheers,

James