[sdiy] (OT) help with DEC branded relays

[Benjamin Riggs]

I guess I should have been more specific to the problem with the relay. On
the amplifier, when the protection light went off at power up, it takes
somewhere between 30 sec to 5 minutes for sound to appear at the speakers.
Measuring the voltage across the protection diode, the voltage jumps to 55V
at the same time the protection LED goes off. I did a continuity test of the
coil and it measures about 4k (seems ok?). doing a continuity test of the
contacts, it takes the same 30sec to 5 mins for them to go closed circuit.

I was thinking maybe the contacts might be faulty, but since both channels
switch at the same time, maybe the coil has fused or something. Either way,
the relay is faulty.

The relay is a 6 pin DPNO, the pcb was designed to accommodate a 8 pin unit.
The pin laypout seems standard, although I have yet to measure it (cant find
my callipers atm).

My first problem is finding the current rating of the device, the amplifier
is rated at 2x200W into 4ohms (which is my speaker impedance), but it is
supposed to be happy driving 2ohm loads (280W if I remember) so I guess it
would have to be reasonably large (12A min so the contacts don't burn out?)

My second problem is removing it. I have tried also to remove the cover of
the relay, unfortunately, the glue is in there too, so I cant get it off
without breaking it.

I was hoping I could just source a replacement and wack it in, but it looks
like I'll have to think bout it some more.

Cheers all for the help.
ben

-----Original Message-----
From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl] On Behalf Of The Peasant
Sent: Wednesday, 29 June 2005 6:00 AM
To: ben.r at iinet.net.au
Cc: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] (OT) help with DEC branded relays

Hi Ben,

I unfortunately have no info regarding DEC relays, but I have repaired 
equipment that uses them by replacing the relay with one removed from a 
scrapped unit. I believe that the coil is rated for 48VDC as labelled.

The problem is most likely the coil wire is broken where it attaches to the 
solder lug on the relay base, on one of the two coil connections. If you get

lucky and have a steady soldering hand, this type of failure *can* be
repaired. 
If they glued the relay to the pcb your best bet may be trying to repair it 
anyways.

Take care,
Doug 
______________________
The Electronic Peasant

www.electronicpeasant.com


Quoting Benjamin Riggs <Ben.r at iinet.net.au>:

> I'm asking the list, cause you guys are always good for answers. To try
keep
> this on topic, the relay in question is out of my amplifier in my lounge
> room/studio, it's a NAD 319 integrated amp.
> 
> Anyways, I my amplifier ceased to output any sound the other day, I just
> opened it up and it seems the relay on the output has failed. Its part of
> the protection circuitry, and it disconnects the output in event of a
fault
> (overheating and short circuit output are the only two I've seen so far,
> oops). The relay in question is labelled top to bottom as follows:
> 
> Type DH2U
> 48VDC
> TV-3
> "couple of funny symbols here"
> DEC
> 
> So far I've been unable to find any info on this part, can anyone please
> help me find info on a replacement or substitute.
> 
> Cheers in advance
> ben
> 
> 
>