Low Voltage Causes Overdrive Shutdown of Amplifier

[WA2WMR]

When I got the Tokyo Hy-Power solid state amp, I had a 240volt line installed for it. This week we had some electrical work done, including installing a new breaker box in the basement. Some of the work required that I remove the radio equipment from the operating desk so it could be moved to allow access to some of the outlets behind it. (not the 240 line).

Last night I reassembled the station and gave it a try. INSTANT amplifier shutdown due to overdrive condition. I had to lower the transceiver output power to about 5 volts to prevent this from occurring, which resulted in an amplifier output of less than 50 watts. After checking connections and referring to the owners manual for a few hours I had an idea. 

Inside the amplifier, there are various combinations of transformer connections for 110/120/130 and 220/230/240 AC supply voltages. Thinking that perhaps I had the transformer connected for 220 and now had 240 at the wall, I whipped out the handy volt meter to check the wall socket. What I found was that I had 120 at my 240 volt outlet. I flipped the amp over and moved the switch to the 120 volt position and found that the trouble had gone away. 

Very Interesting.

[K3MRI]

Hey Lind. What's bizarre is that the 240v outlet went to 120v. Is it just that outlet or did all of your 240 go away.

Also funny because this very morning, Maria and I were having a conversation, on a different topic, and the 110/220 discussion was a part of it 🤔

[WA2WMR]

That is my only 220 V outlet. The washer and dryer are 220 but a different circuit. As far as I know there was no trouble there unless they fixed that as part of the fix for my outlet.

[K3MRI]

On 11/4/2022 at 1:37 PM, WA2WMR said:

That is my only 220 V outlet. The washer and dryer are 220 but a different circuit. As far as I know there was no trouble there unless they fixed that as part of the fix for my outlet.

Clearly the electrician did something. This said, my two pennies, I would prefer working the amp on 220 (or 240...). In either case, the electrician should, at least, tell you what happened.

[WA2WMR]

I wasn't concerned with how he made the mistake; he fixed it without charge. He rewired every regular outlet in the house and this outlet is the same as other outlets (unlike the ones for the washer and drier which have flat contacts arranged differently). 

[K3MRI]

16 hours ago, WA2WMR said:

I wasn't concerned with how he made the mistake; he fixed it without charge. He rewired every regular outlet in the house and this outlet is the same as other outlets (unlike the ones for the washer and drier which have flat contacts arranged differently). 

Sorry, confused... so is that amplifier outlet now at 220 or 110?

[WA2WMR]

I misunderstood what you said. He was engaged to rewire the outlets in the house (it's been several years so I don't remember the reason for rewiring). In the process, he replaced the breaker box and other stuff. When he put it back together, he wired the 220 outlet just like the others.

220

Perhaps I should do something to indicate that it is not normal (abnormal - or A. B. Normal if you prefer). I wonder if I can get a red outlet cover.

 

 

[K3MRI]

That is so so so weird that you said that about the red cover. That is literally the color my dad had painted our 220 outlets in the house. So so weird!!