Bottlehead Forum

Bottlehead Kits => Moreplay => Topic started by: Happy Ghost on September 20, 2022, 11:03:36 AM

Title: Really stumped... Cross talk between inputs [resolved]
Post by: Happy Ghost on September 20, 2022, 11:03:36 AM

Hi All,

I had my Moreplay running successfully for some time. But recently there is quite a lot of cross talk between the various inputs. There are 3 problems I saw:

1. Between L1 and L2, there seems to be a short. I read 7.5 ohms across them. I can hear it when I switch inputs too..
2. There is 85.4 kilohm between the solder tab of L3 and the center hole.
3. There is 53.5 kilohm between the solder tab of R3 and the center hole.

I checked the connections and they look OK to me. I am attaching some pics with this post. Can someone help me troubleshoot.

Thanks in advance!

Title: Re: Really stumped... Cross talk between inputs
Post by: Paul Birkeland on September 20, 2022, 03:12:43 PM

What resistance to ground do you get from the center of L1 to ground and the center of L2 to ground (with the selector on input 3)?

Title: Re: Really stumped... Cross talk between inputs
Post by: Happy Ghost on September 20, 2022, 03:46:22 PM

I get 86 kilo ohm for both (L1/L2) with the input selector on 3

Title: Re: Really stumped... Cross talk between inputs
Post by: Paul Birkeland on September 21, 2022, 04:10:33 AM

I would look for a possibility that some of the CAT5 wire has gotten hot enough that the jacket has melted and the wires inside are touching.  It would probably be enough to just be sure that wherever CAT5 wires touch other CAT5 wires that you are able to spread them apart.

Title: Re: Really stumped... Cross talk between inputs
Post by: Happy Ghost on September 21, 2022, 05:06:58 AM

Yup.. that was it.. a very small part of it was touching each other with the jacket melted.. and to think that I had checked everything before I posted on the forum :( this is so embarassing..

thanks PB!

Title: Re: Really stumped... Cross talk between inputs
Post by: Paul Birkeland on September 21, 2022, 05:18:42 AM

I would have never thought of it except that I ran into the same issue with a repair yesterday.  I'm glad you found it!

Title: Re: Really stumped... Cross talk between inputs [resolved]
Post by: Mucker on September 26, 2022, 07:26:19 AM

I had the same problem with my build. The middle input had muted sound in one channel. The other 2 were fine. It was pretty easy to track down as it's only twisted pair's between the rotary switch and RCA's. The short was confirmed with meter.

The problem for me was the wire twist existed right up to, and very close to he RCA and the heat was too much because of the close proximity causing the jackets to melt and wires to short. Completely hidden from sight it was. I think leaving the wire pairs untwisted for a short length before securing to RCA's can help avoid this issue.