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According to my Kenwood TS-530 S radio manual - it's a straightforward simple switching of two wires - to convert the radio from 110-V to 220/240-V.

That was done -according to the schematic and picture - in the manual. However there is a rather loud hum - presumably the transformer - after the conversion. Since this was designed originally to operate on 60 Hz. - at either voltage. Did I miss something - in needing to also have a circuit - to change to 50 Hz?

If I do need to make a new circuit. I do have a slide switch from another device - which has the 50/60 Hz circuit - built in -that I think I can adapt.

The TS-530 S is specified as running on 50/60Hz so there should be no problem.

If it is more than ten years old you may like to consider putting in new electrolytic capacitors, especially the big fat ones. Make sure you understand the gas venting arrangements

Please note that you need to be licensed before using the transmitter section. Check your local transmission power regulations, they may differ from those in the country of origin.

The governing body in the UK is OfCom and more information is available from the RSGB. On HF the limits to power are 10W, 50W, 100W and 400W depending on the level of license and frequency band. Transmision is only permitted on specified frquency bands.

Thanks Mike - for your response. I'd like to clarify my ignorance here. I am a still licensed Ham - in the U.S./Israel. I've just returned to active operating on HF. However - I haven't been able to crack/study a electronics book - since 1977. So - forgive me - I'm a bit behind and rusty - and I may be relying on some faulty electronics memory.

My KW - is the American Version - which is only 110-V - and doesn't have the switch - to change from 60 - to 50 Hz - like the Eu/Korean version.

Your correct. The KW manual does indicate that - it will operate on 50/60 Hz. Though on the last page - it mentions having to use the S3 switch - to make the change. Mine - doesn't have the switch. So - I thought maybe that meant that - the transformer - could be switched to U.S. 220-V - but might stay at 60 Hz. Because - there isn't a switch circuit - to make the 50 Hz change.

The instructions on how to convert to 220-V - doesn't mention that there is a automatic change of Hz. It only mentions how to change the voltage (and the S3 switch) - and once done - change the fuse - from 6-A - to 4-A.

So my question was - to know whether or not - if a circuit needs to be added - to complete the 50 Hz change.

I'm also going to review the procedure - to make sure we made all the correct changes - the first time - and see if it will work.

There is no switch for 50/60Hz. It simply requires that the transformer has enough core material, measured in that abstruse unit volt-seconds. Any switch selects voltage.

Glad to hear you are a licensed ham. You will appreciate my reasons for mentioning licensing together with freq and erp regs.

Mike's answers so far are right on but I'll add a bit: Transformers designed for 50 Hz will normally work comfortably on 60 Hz but the reverse is not true. Whether or not a transformer designed for 60 Hz will work on 50 Hz depends on the designer's courage. If he (or she) put in a good big iron core it will probably handle 50 Hz ok but if a small core was used it will be close to magnetic saturation at 60 Hz and at 50 Hz will be well into saturation resulting in a loud hum and more heating. If the filter capacitors check out ok (Mike's suggestion) there's not much more you can do.

Hi Foxx - thanks for your response. I had forgotten about - looking at core size. DUH.

And - I don't recall - ever learning about - gas venting for electrolytic capacitors. But like I mentioned to Mike. I haven't done any studying - since about 1977 - due to military and other causes.

So - I guess my question(s) are: What am I looking for - on gas venting? And - when I go back into the rig - what formula - and or what do I need to check - to determine if - the core size is correct?

Gas venting on small capacitors can be seen as a couple of lines which make a weakness in the case where gases can escape relatively slowly making a small bang rather than an explosion. Large capacitors such as the supply smoothing capacitors on this unit have visible vents, usually between the terminals. I worked for one large firm where the draughtsmen ignored the vents and drew enough holes in the pcb for the terminals but not the vents. When connected backward as sometimes happens the capacitors built up pressure and the vents were blocked. Result - holes in the roof and somewhat surprised test staff.

The only way I know of testing the transformer is that if you can fry eggs on it there's not enough core. But in this case they say it will do 50/60Hz and this is good enough for me.

Real hum is a clean 50Hz but smooothing capacitor hum will be a jagged 100Hz.

Go by the rating nameplate on the transformer or equipment. If it says 50/60 Hz you can use it on both. If not you can only use it on the Hz that it says. My experience with transformer design is limited to a few problems way back in university 64 years ago but I do remember that sizing the core depends on the type of steel used, the magnetic path and the excitation current, heating and noise you can tolerate, so there is not much you can check besides the nameplate.

HI Foxx, Thanks for the response - and the info.

I'll try to open the rig - as soon as I can - and take a look.

I also may try to find one that's rated correctly.

Well, did you look, and was there a plate? I'd reckon not, because this was a custom transformer made to a Kenwood number. Better to trust the Kenwood engineers when they tell you in the spec, page 2, that it runs on 50/60Hz.

And if you still have not seen the gas vents on an electrolytic capacitor, just have a decco at one. It is either some scribed lines on the case or, on the larger capacitors, an actual vent same end as the terminals. They don't teach you about them at school, because they are H&S, rather than theory.

Hi Mike - thanks for the response. Because the manual said that - it was 50/60 Hz. I took that - at face value. Until we had the problem with the hum. Right now - with some medical issues - I haven't gotten back to reopening my rig. I hope to get into it - in the next few days. BTW - I thought we'd checked it back on 110-V - but that hasn't been done. It was rewired for 110-V. But - the 110-V plug was cut off - and thrown away - as was the 220 plug. I'm now trying to find a replacement 110-V plug - I want to put it back on the transformer - to check it out on 110-V first. I'll try to post back here - what I find.

Thanks, Gersham, sorry to hear you have had a medical problem. Me too, had a stroke last year and need lots of help so am in a home without any prospect of getting back to real life.

All the best with your rig. It is always difficult to diagnose problems at long range. Suggest you might find several items by googling TS530 S problems. This gives some owner experiences.

HI Mike, I'm sorry to hear that - you've got heart problems - and are in a home - though hopefully - with great assistance - and therapy - to get you back on your feet.

I'm a 70% Disabled American Vet. So far - thank G-D. I'm not in an assisted home.

I - will include you - in my daily prayers for the sick. May G-D bless you - mentally - emotionally - physically - and financially - with all your needs.