Kenwood KA-7100 Relay Question

kenwood1986

New Member
Hello AK I have a Kenwood KA-7100 which I think has a bad relay . The information I got from the relay is as follows
S514030
24V. DC
Type MS4U
DEC japan.
If anybody has information on what a replacement relay would be for this all help would be greatly appreciated ! Thanks !
 
The only thing that ever seems to go 'bad' with these relays is that the contacts tend to get worn out and channels drop out from time to time. If the relay is not actuating at all a few seconds after power up, then there are almost certainly other issues.

Contact wear aside, the relay is probably the most reliable component in that chassis.

(the relay is replaced with an Omron MY4-02-DC24, but swapping it out will be a waste of time unless it simply needed replacement because of the condition of the contacts)

(oh, and nearly every 7100 I ever worked on had a bad relay driver transistor...)
 
Thanks ! With this unit I can power it up , and will have no left channel , I can get that to work come back later and the right channel will be out and vise versa . I have the DC offset and bias adjusted as close as I can get it .
 
Possibly flaky relay contacts, but front panel switches and pots in need to a thorough DeOxit bath are just as likely.
 
Hey , I took the cover off of the relay . The contacts were fairly black like they had been arcing . One was blacker than the other three . I went over them with 1000 grit wet/dry sandpaper , then applied deoxit and then whipped it off . I also aligned the contacts a little better than they were . I also re soldered the joints for the relay to the board . So far so good , will keep you updated
 
The contacts are plated, and the plating is quite thin. If the scrubbing cured things, then I'd replace the relay with a new one, as the sandpaper likely has removed the plating and your problem will return.

Omron MY4-02-DC24, at Mouser or Digikey.
 
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