EEVblog Electronics Community Forum
A Free & Open Forum For Electronics Enthusiasts & Professionals
Welcome,
Guest
. Please
login
or
register
.
Did you miss your
activation email
?
1 Hour
1 Day
1 Week
1 Month
Forever
Login with username, password and session length
This topic
This board
Entire forum
Google
Bing
Home
Help
Search
About us
Links
Login
Register
EEVblog Electronics Community Forum
»
Electronics
»
Beginners
»
Beginner: any idea why R43 would have disintegrated?
« previous
next »
Print
Search
Pages: [
1
]
Go Down
Author
Topic: Beginner: any idea why R43 would have disintegrated? (Read 224 times)
0 Members and 1 Guest are viewing this topic.
rthorntn
Frequent Contributor
Posts: 436
Country:
Beginner: any idea why R43 would have disintegrated?
«
on:
Yesterday
at 12:17:48 am »
Hi,
I have a subwoofer that powers on but doesn't work.
I've dismantled it and the amp (a rebadged Dayton SPA250) has the legs of a resistor at R43 but no body?
I found a diagram that's has it as a 10K connected between earth and the soft-limit circuit, I'm assuming a mains power surge but want to be sure before I replace it, I'm guessing it was a 1/6W or less as the body "gap" is tiny?
Thanks
Richard
Logged
bostonman
Super Contributor
Posts: 2021
Country:
Re: Beginner: any idea why R43 would have disintegrated?
«
Reply #1 on:
Yesterday
at 12:50:09 am »
I may be wrong, but that looks like a thermistor since it has an oval circle around it.
Logged
The following users thanked this post:
rthorntn
rthorntn
Frequent Contributor
Posts: 436
Country:
Re: Beginner: any idea why R43 would have disintegrated?
«
Reply #2 on:
Yesterday
at 12:55:31 am »
Thanks, does a thermistor make sense, do they just explode then, would it cause the symptom I'm seeing, power on, no sound?
Logged
bostonman
Super Contributor
Posts: 2021
Country:
Re: Beginner: any idea why R43 would have disintegrated?
«
Reply #3 on:
Yesterday
at 01:18:27 am »
I'm not exactly sure how the circuit works, but point A is connected to the left side near the J1 connector.
The circuit marked point A is also connected to standby and a temp node, so it's possible the circuit thinks the system is too hot and not turning on.
Logged
The following users thanked this post:
rthorntn
rthorntn
Frequent Contributor
Posts: 436
Country:
Re: Beginner: any idea why R43 would have disintegrated?
«
Reply #4 on:
Yesterday
at 01:20:18 am »
Thanks, I'm reading up on it now, they can explode and they do act as a sort of surge protection, I just had a good look at the soft-limit PCB and I don't see anything obviously wrong. Probably just get a 10k thermistor and solder it in?
Logged
bostonman
Super Contributor
Posts: 2021
Country:
Re: Beginner: any idea why R43 would have disintegrated?
«
Reply #5 on:
Yesterday
at 01:26:08 am »
Looking at the thermistor chart, it's 10k at 77 degrees F and the resistance decreases as temp increases.
Maybe stick a 10k resistor in the spot and see if it turns on.
Logged
The following users thanked this post:
rthorntn
Print
Search
Pages: [
1
]
Go Up
« previous
next »
Share me
Smf
EEVblog Electronics Community Forum
»
Electronics
»
Beginners
»
Beginner: any idea why R43 would have disintegrated?
There was an error while thanking
Thanking...
EEVblog Main Site
EEVblog on Youtube
EEVblog on Twitter
EEVblog on Facebook
EEVblog on Odysee