Possible damage to the radio by using over voltage PSU? - Page 1
Forum section: electronics / rf-microwave

author: vinlove
author_rank: Frequent Contributor
timestamp: May 15, 2025, 03:31:11 pm
content: I got this old shortwave radio which is supposed to be used with 6V psu (centre negative).But the supplied PSU looked crummy, and it output 10V.Due to possible damage to the radio, the PSU was put away not being used at all.The radio powers on with 4x D type batteries, but wondering if the previous owner has been using the radio with the faulty PSU outputting 10V instead of 6V, then could this have damaged the radio in some way? Although it powers and seems working, it sounds a but mushy.What is the maximum voltage DC PSU which can be used with 6V nominal voltage radio without damaging the parts inside?

author: TimFox
author_rank: Super Contributor
timestamp: May 15, 2025, 04:06:51 pm
content: Ill-posed question. It depends greatly on the radio's circuitry.What is the make/model, and do you have a schematic diagram, or manual, or indication on the back panel about DC power?

author: tunk
author_rank: Super Contributor
timestamp: May 15, 2025, 04:19:42 pm
content: Is that 10V at no load?If it's an old type unregulated PSU with a transformer,rectifier and smoothing capacitor, then the voltage willdrop when you load it.

author: vinlove
author_rank: Frequent Contributor
timestamp: May 15, 2025, 05:09:27 pm
content: Quote from: TimFox on May 15, 2025, 04:06:51 pmIt is a Chinese made radio, no documents whatsoever with the radio.In the back panel, it says "6V DC centre negative" or "4x Type D batteries".The PSU input socket on the side says "6V DC".The supplied PSU is a no-name cheap PSU with multi voltage selection - it outputs 10V or over on all voltage settings. The settings are 3, 6, 9 VDC from 240V AC.

author: vinlove
author_rank: Frequent Contributor
timestamp: May 15, 2025, 05:11:10 pm
content: Quote from: tunk on May 15, 2025, 04:19:42 pmNot sure on the PSU. It looks a cheap no-name PSU with 3, 6 and 10V settings. They all output 10+ VDC.

author: radiolistener
author_rank: Super Contributor
timestamp: May 16, 2025, 12:36:23 am
content: Yes, some circuit components may be burned due to overvoltage. So, the radio may work partially, with some functions not working, or it may have distortion issues, or not work at all. It depends on the circuit and luck.

author: vinlove
author_rank: Frequent Contributor
timestamp: May 16, 2025, 08:56:12 am
content: Quote from: radiolistener on May 16, 2025, 12:36:23 amPowered on the radio with 4x D cell batteries, and it seems work ok. Just wondering if it would keep working with no sudden death of the radio.If it works ok, maybe it has not been damaged?

author: radiolistener
author_rank: Super Contributor
timestamp: May 16, 2025, 09:10:56 am
content: Quote from: vinlove on May 16, 2025, 08:56:12 amyes, it is possible that no visible damage occurred. However, internal components may still be affected, even if basic functions appear to work normally. For example, it might operate but draw excessive current or show reduced sensitivity.To ensure the device is fully functional, test it in all operating modes, measure current consumption, and check sensitivity. If all parameters are within normal range, it’s likely that no critical damage occurred, but hidden issues can't be ruled out without thorough diagnostics.

author: tunk
author_rank: Super Contributor
timestamp: May 16, 2025, 12:06:15 pm
content: You could open it and see if you can find voltage specs for all chips, transistors, etc.