Seeburg SCH1-4 APU Missing

[sooner]

The speakers are about 30 ohms. Higher than typical speakers that range from 4 to 16 ohms but they work fine with my amp which is designed for 4 to 8 ohms.

[spetersen]

When I wrote that, I thought the HVG and the photodiode ground were tied together, Your second schematic should work, except HVG needs to go to ground instead of 5v and HV needs to go to 5v

The speakers work fine with the amp I'm using, maybe test the speakers with a 9v battery , just a quick brushing of the wires across the battery should make noise.

The 200 ohm resistor is to reduce noise.

Attachments:

[ScotK]

So I touched the contacts to a 9v battery a few times and not even a whisper from the stock speakers.

[Ron Rich]

A 9V battery can blow speakers ! --use a 1.5 for that test !! Ron Rich

[ScotK]

I think they might already be blown. Next step is I'm going to dismount them and hook them up to a stereo that I know has more than enough power to drive it, just to see if the speakers work at all. I can also try hooking the amp to one of the stereo speakers, it should be able to drive one of them enough to get some audible volume, so I know whether the amp is working or not.

[sooner]

I check resistance to test for a bad speaker. Doubt you blew them using the 9V battery to test them or you would have heard a loud pop to begin with.

[spetersen]

It wouldn't blow them, unless the leads were held against the battery for more than a few seconds, If they are 30 ohm speakers, they would be able to take 9v for a while, it would only be 2.7w. I wasn't sure if the 1.5v battery would be loud enough to be heard on the small speakers. resistance on a meter would also work.

If your speakers are dead, I may have some TV speakers that can be adapted to fit, that you can have for free, just pay shipping.

[ScotK]

The original speakers are definitely dead... hooked one up to the stereo and got nothing. Then I checked them with a meter set to resistance, it reads no connection across the leads on both speakers. I need new speakers.

Ron, any suggestions for replacement speakers?

[Ron Rich]

Hi Scott,
Sure-- Read our FAQ's section--many parts suppliers are listed there-- should be plentiful-- Ron Rich

[scudie]

Hi Scott
That's really unlucky I have had quite a few of these SC and SCH wallbox's over the last three years and never had any with a faulty speaker.
First one I had was missing the speakers, I fabricated a couple of brackets and  fitted a couple of small Sony personal stereo speakers they worked a treat.
Scudie

[Ron Rich]

Hi Guyz,
I have restored hundreds of them-- I think I changed two speakers in one WOM, that came in for repair, once. Asked the owner how he blew the speakers and he told me-- Hooked them up to the 50 watt tap, and cranked up the volume control-- About 3-4 seconds --- foof !! LOL Ron Rich

[spetersen]

I imagine it could be done if miswiring the 24v to the speakers

[ScotK]

Looks like they're going to be about $60 apiece to have them rebuilt, plus shipping, per Orban Audio from the FAQ.

[ScotK]

Dec 18, 2019 22:25:09 GMT Ron Rich said:

Hi Guyz,
I have restored hundreds of them-- I think I changed two speakers in one WOM, that came in for repair, once. Asked the owner how he blew the speakers and he told me-- Hooked them up to the 50 watt tap, and cranked up the volume control-- About 3-4 seconds --- foof !! LOL Ron Rich

The APU was missing on mine and on a few others the person had that I got mine from... Sounds to me like somebody raided them for parts.  Makes me think something happened to several of them at once when they were all hooked up.  Miswire, lightning strike, or whatever. Guess I should count myself lucky nothing else was missing or damaged.  

[spetersen]

If you want my free for shipping speakers, I can dig them out and post pics

You could also try parts wanted