power supply for Sony MZ-R70 (AC-MZR5)

[lipwak]

Hi,

I also have a Sony MZ-R70*. I can get it to record but the power supply for it (AC-MZR55) does not power it. Batteries work fine. So, how do I tell if the power supply is dead or is there something I am doing wrong that is preventing it from working?

I did try to hook up a battery tester, using the prongs to try to attach the positive to the inside tip and the negative to the shield but it didn't register when plugged in. I may not have been making contact though. Is there any other test I can do?

Many thanks. If I can't get this power supply to work, I'll just keep using (rechargeable) batteries.

Cheers,

John L

* I also started a thread on a Sharp MD-MS702 MK not recording.

[jim.hoggarth]

The old, bulky, AC-MZR55 is transformer based, not SMPS. Presumably you don't have a multimeter / voltmeter? The usual reason for these to fail is the thermal fuse on the transformer primary. If you can't do a resistance/continuity test on the mains input, try using a plastic-handled screwdriver as a stethoscope. Put the metal shaft on to the top of the adapter body, and place the plastic handle into/against the ear hole. Turn on teh mains, and you should hear a 50Hz (UK) or 60Hz (US) low frequency mains buzz. If not, the fuse has blown. Goodbye adapter.

The next possible cause is the power cable going open circuit. Usually this happens at the adapter body end, as it exits the plastic strain-relief sheath. You can often see physical damage to the cable here. Caused by winding/unwinding the cable from around the adapter body too often (that will teach you to be neat and tidy!)

Another possible is that the yellow plastic end cap has come away from the 3v plug end, and got jammed in the R70's power socket so the adapter plug no longer goes all the way home, so cannot make contact.

Without a multimeter there's not much more you can do but guess. Beg/borrow a multi-adapter and try it on your R70?

Jim