Russian R154-2M - UK Vintage Radio Repair and Restoration Discussion Forum

Sean Williams · 28th Aug 2013, 12:22 pm

Currently having a play with this Reciever - very little available info - have ordered what I think to be a repair manual from Germany.

Biggest current issue however is that of the case being around 118v AC above true earth.

Now, I really wish to avoid the whole PME/Mains Earth/True Earth debate, but need a sanity check.

I have checked true earth to mains earth voltage in my shack - I get about 2v AC, which is normal.

I have also checked other equipment in the shack to see if it is an issue with the power supply to the antenna tuner - again, about 2v from mains earth to each bit of kit.

So, I was thinking that there may well be a couple of caps across the mains to chassis on this unit - have meggered the various points within the set to chassis, including phase and neutral to chassis, all test perfectly.

Looking for ideas and inspiration!
Cheers
Sean

Alistair D · 28th Aug 2013, 12:31 pm

Connect a suitable resistor say 10k ohms between the chassis and mains earth. The voltage across it will tell you how much current is available. If it is only a mA or two it should be safe to earth the chassis permanently. It would still be worth finding the source of the current to make sure it is not a fault.

Al

Sean Williams · 28th Aug 2013, 1:56 pm

Hmm, 4mA through 10K to deck......

Not healthy.

Being modular (to an extent) I have been able to narrow it down to the power supply unit/IF stage chassis.

I think circuit diagrams are required - lots of odd things happen inside this set.

Safety is decadent Komrade.

Alistair D · 28th Aug 2013, 2:48 pm

That would equate to a 47nF capacitor from L to E. I have just looked at a filtered IEC inlet and the equivalent cap is 2.2nF. Big difference.

Al

Radio Wrangler · 28th Aug 2013, 3:14 pm

If you have one of those multimeters with a capacitance range, give it a try.

David

Sean Williams · 28th Aug 2013, 4:24 pm

Well, had a rummage through the set - there is a discrete mains filter, with 6 poles!

Sadly it would appear that the caps used are a little marginal at 240v - insulation resistance is fine at over 50Meg!

With the filter bypassed leakage drops to a very acceptable 0.2ma

I think a new, modern mains filter will be in order.

Radio Wrangler · 28th Aug 2013, 6:08 pm

I suggest a Corcom or Japanese mains filter. Some Schaffner ones, I found, have golden stink-bombs inside.

David

Sean Williams · 28th Aug 2013, 8:26 pm

Well, it gets better - the BFO has now decided to stop working! - Manual on it's way from Germany - My German is much better then my Russian!

AC/HL · 28th Aug 2013, 8:50 pm

Hi Sean,
You're welcome to one of these, from a box of oddments I acquired recently.

Sean Williams · 29th Aug 2013, 10:09 am

Thanks Bill, I have rebuilt the discrete filter using modern components - seems a shame to dump such a nice diecast chassis - it also filters all of the HT and LT lines that feed other modules.

Onto the BFO when the manual arrives.

28th Aug 2013, 12:22 pm	#1
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,517	Russian R154-2M Currently having a play with this Reciever - very little available info - have ordered what I think to be a repair manual from Germany. Biggest current issue however is that of the case being around 118v AC above true earth. Now, I really wish to avoid the whole PME/Mains Earth/True Earth debate, but need a sanity check. I have checked true earth to mains earth voltage in my shack - I get about 2v AC, which is normal. I have also checked other equipment in the shack to see if it is an issue with the power supply to the antenna tuner - again, about 2v from mains earth to each bit of kit. So, I was thinking that there may well be a couple of caps across the mains to chassis on this unit - have meggered the various points within the set to chassis, including phase and neutral to chassis, all test perfectly. Looking for ideas and inspiration! Cheers Sean __________________ Engineers make things work and have spare bits when finished

28th Aug 2013, 12:31 pm	#2
Alistair D Nonode Join Date: Jan 2010 Location: Edinburgh, UK. Posts: 2,008	Re: Russian R154-2M Connect a suitable resistor say 10k ohms between the chassis and mains earth. The voltage across it will tell you how much current is available. If it is only a mA or two it should be safe to earth the chassis permanently. It would still be worth finding the source of the current to make sure it is not a fault. Al __________________ I won't tell you how I discovered that.

28th Aug 2013, 1:56 pm	#3
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,517	Re: Russian R154-2M Hmm, 4mA through 10K to deck...... Not healthy. Being modular (to an extent) I have been able to narrow it down to the power supply unit/IF stage chassis. I think circuit diagrams are required - lots of odd things happen inside this set. Safety is decadent Komrade. __________________ Engineers make things work and have spare bits when finished

28th Aug 2013, 2:48 pm	#4
Alistair D Nonode Join Date: Jan 2010 Location: Edinburgh, UK. Posts: 2,008	Re: Russian R154-2M That would equate to a 47nF capacitor from L to E. I have just looked at a filtered IEC inlet and the equivalent cap is 2.2nF. Big difference. Al __________________ I won't tell you how I discovered that.

28th Aug 2013, 3:14 pm	#5
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,874	Re: Russian R154-2M If you have one of those multimeters with a capacitance range, give it a try. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

28th Aug 2013, 4:24 pm	#6
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,517	Re: Russian R154-2M Well, had a rummage through the set - there is a discrete mains filter, with 6 poles! Sadly it would appear that the caps used are a little marginal at 240v - insulation resistance is fine at over 50Meg! With the filter bypassed leakage drops to a very acceptable 0.2ma I think a new, modern mains filter will be in order. __________________ Engineers make things work and have spare bits when finished

28th Aug 2013, 6:08 pm	#7
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,874	Re: Russian R154-2M I suggest a Corcom or Japanese mains filter. Some Schaffner ones, I found, have golden stink-bombs inside. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

28th Aug 2013, 8:26 pm	#8
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,517	Re: Russian R154-2M Well, it gets better - the BFO has now decided to stop working! - Manual on it's way from Germany - My German is much better then my Russian! __________________ Engineers make things work and have spare bits when finished

28th Aug 2013, 8:50 pm	#9
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Russian R154-2M Hi Sean, You're welcome to one of these, from a box of oddments I acquired recently. Attached Thumbnails

29th Aug 2013, 10:09 am	#10
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,517	Re: Russian R154-2M Thanks Bill, I have rebuilt the discrete filter using modern components - seems a shame to dump such a nice diecast chassis - it also filters all of the HT and LT lines that feed other modules. Onto the BFO when the manual arrives. __________________ Engineers make things work and have spare bits when finished