0
\$\begingroup\$

I have inherited a fairly old Sharp amplifier which does not power on anymore. After poking around with a multimeter we notice that power stops flowing at a DEC Type DG1U TV-5 relay which is rated 8(2)/60A / 18VDC. My plan is now to replace this, however, there only seem to be relays of this type with 8/60A / 12VDC for purchase online.

Would 12VDC be a suitable replacement? We don't plan on driving a huge sound system (nor very loud) with this - at most a couple smallish tower speakers "rated for max. 90W" (what the sticker says).

I should also maybe note that I'm in Austria where we have 230V.

\$\endgroup\$
2
\$\begingroup\$

The 18VDC refers to the coil drive voltage. If you just replace an 18 volt relay with a 12 volt relay, the coil will get 50% more voltage than it is rated for, and may (will) overheat. However, you can easily fix this. The 12VDC models have a coil resistance of 275 ohms. If you wire a 137 ohm resistor (1/2 watt power rating) in series with the coil, the resistor will drop 6 volts and the coil will be driven correctly. Since finding a 137 ohm resistor may be difficult, a 120 or 150 ohm resistor will suffice.

\$\endgroup\$
  • \$\begingroup\$ A pot could be used or a 137 could be found in a bag of wide tolerance resistors maybe \$\endgroup\$ – JFA Apr 27 '14 at 2:35

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.