Akai GX280-SS - UK Vintage Radio Repair and Restoration Discussion Forum

stuart_morgan_64 · 4th Nov 2016, 7:53 pm

I have spent a long time getting this machine to run. Its all now working and I thought best to do earth leakage test. It reads dead short. With a ohm meter about 10M.

On the power supply the transformer is used as a auto transformer to run some solenoids. Are the readings I am getting OK.

Advice please. Thanks.

The manual is availble on Hi-Fi Engine.

radiotechnician · 17th Nov 2016, 8:34 am

Could you clarify what you mean by dead short ? Was this between the line cord pins
and the chassis ?

stuart_morgan_64 · 19th Nov 2016, 7:07 pm

With a multimeter 10M plus. With a 500v insulation tester reads short between L mains and chassis.

Radio Wrangler · 19th Nov 2016, 7:23 pm

It sounds like something is breaking down at that voltage.

First off, I'd look in the circuit diagram for capacitors between line and chassis as well as neutral and chassis. Remove and re-test. replace with correct type (Class-Y) if faulty.

David

TIMTAPE · 21st Nov 2016, 2:23 am

I have the same model. It's rarely used. Just looked at it.

At some stage I had written a note for myself on it:

Leakage current from live mains to chassis: 0.25mA.

Must check my machine out also to determine cause of leakage.

Tim

radiotechnician · 24th Nov 2016, 1:00 pm

What is the DC resistance between the line cord and the chassis ?
The measurement should be done with a multi meter, preferably an analog type.

If there is a low resistance , in the tens of ohms, the fault may be in the transformer or motors.

From the DC resistance, an inductance meter can indicate if it is in the motors of transformer.

It also may be in the KD-A-1001 system control board.

I have two versions of the 280D SS in my Akai schematic register

Does the machine function, despite your test ? (Until resolved it may be unsafe}

4th Nov 2016, 7:53 pm	#1
stuart_morgan_64 Heptode Join Date: Aug 2004 Location: Woodbridge, Suffolk, UK. Posts: 501	Akai GX280-SS I have spent a long time getting this machine to run. Its all now working and I thought best to do earth leakage test. It reads dead short. With a ohm meter about 10M. On the power supply the transformer is used as a auto transformer to run some solenoids. Are the readings I am getting OK. Advice please. Thanks. The manual is availble on Hi-Fi Engine.

17th Nov 2016, 8:34 am	#2
radiotechnician Pentode Join Date: Jan 2013 Location: Powell River, British Columbia, Canada. Posts: 217	Re: Akai GX280-SS Could you clarify what you mean by dead short ? Was this between the line cord pins and the chassis ? __________________ Steve Dow VE7ASO

19th Nov 2016, 7:07 pm	#3
stuart_morgan_64 Heptode Join Date: Aug 2004 Location: Woodbridge, Suffolk, UK. Posts: 501	Re: Akai GX280-SS With a multimeter 10M plus. With a 500v insulation tester reads short between L mains and chassis.

19th Nov 2016, 7:23 pm	#4
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,868	Re: Akai GX280-SS It sounds like something is breaking down at that voltage. First off, I'd look in the circuit diagram for capacitors between line and chassis as well as neutral and chassis. Remove and re-test. replace with correct type (Class-Y) if faulty. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

21st Nov 2016, 2:23 am	#5
TIMTAPE Octode Join Date: Jul 2006 Location: Perth, Western Australia Posts: 1,969	Re: Akai GX280-SS I have the same model. It's rarely used. Just looked at it. At some stage I had written a note for myself on it: Leakage current from live mains to chassis: 0.25mA. Must check my machine out also to determine cause of leakage. Tim

24th Nov 2016, 1:00 pm	#6
radiotechnician Pentode Join Date: Jan 2013 Location: Powell River, British Columbia, Canada. Posts: 217	Re: Akai GX280-SS What is the DC resistance between the line cord and the chassis ? The measurement should be done with a multi meter, preferably an analog type. If there is a low resistance , in the tens of ohms, the fault may be in the transformer or motors. From the DC resistance, an inductance meter can indicate if it is in the motors of transformer. It also may be in the KD-A-1001 system control board. I have two versions of the 280D SS in my Akai schematic register Does the machine function, despite your test ? (Until resolved it may be unsafe} __________________ Steve Dow VE7ASO