Murphy A24C - UK Vintage Radio Repair and Restoration Discussion Forum

Ian B · 13th Apr 2009, 9:06 pm

I bought a very tatty murphy A24C (console) at a Radiophile auction last year. When I got it home I discovered that things were even worse! It looked like the chassis had been dropped - output valve and rectifier both smashed, one of the smoothing electrolytics bent. Also, the wavechange switch was falling to bits. The switch blades were originally rivetted to the paxolin base with aluminium rivets. An attempt had been made to repair some by soldering (brass to aluminium ?) and another by a small nail with the end bent over (AAgh).
Nothing daunted, I thought I'd do a quick bodge-up to see how it really was; the switch contacts are all open on LW, so I could leave that for later.
With new reservoir and smoothing electrolytics, and THAT condenser wired in, a U12 and an AC2Pen in place, I powered up. Loads of horrible buzzing, but no tuneable station. Voltage readings on valve bases all good.Thinks - "condenser block", most of the wax caps and a lot of the resistors are inside a tin box under the chassis.
Having carefully labelled all the leads before disconnection I checked for resistance readings - all caps very leaky (surprise!). I also found that all the resistors were at least double their correct value.
Later that same weekend, refitted condenser block, switched on - exactly the same

!
We've gone too far now to give up. So, remove switch assembly, drill out old rivets, remove rusty nail, rivet everything togther firmly and clean contacts. Refit switch, try MW. Five live on top of various other stations in several places

Then I noticed that reception was greatly improved if I held the tuning spindle instead of the knob

try earthing tuning condenser body - loads of stations loud and clear on both bands. Remove condenser and bracket, tighten screws underneath holding condenser to bracket, refit and replace crumbling connecting wires.
Now we're really motoring..... except it won't work below 300m

. Try my spare AC TP - no different. Not oscillating, but why. Check voltages on V1, amazed to find it works beautifully when I hold the meter probe on the oscillator grid. Check circuit diagram again, "oscillator grid stabiliser" should be 3K2, measures well over 7K. Replace it with a new 3K3 and HOORAY! Now we'll restuff the (formerly) wet electrolytics to finish the job off properly.
What a fantastic sounding set, it's been belting out Pirate Gold all afternoon. The huge speaker gives it plenty of bass without being boomy, and the whole performance is excellent.
Now that just leaves the cabinet to do.....

I feel I've learned quite a lot from this beast, and certainly had a wet weekend's fun with it.

Ian Blackbourn

Tazman1966 · 13th Apr 2009, 9:23 pm

Hello Ian.

I get the feeling that most of us get past a point of no return when starting a restoration and pretty early on too

Well done and I look forward to seeing the finished article.

Cheers,

chipp1968 · 14th Apr 2009, 8:41 am

I think this is the model with rosewood veneer at the top and mahogany lower section and solid light wood contrast between te two . I like murphy console sets . I have this model which was restored proff locally over 10 years ago , yet ive never had it going properly . Now I have a decent aerielearth system I should drag it down .It need s completely stripping and re polishing which is one reason why its upstairs .. cant face it at the mo.This thread is making me think about it which is good .I also have an unrestored A28 as well which needs stripping as well

These sortof sets really need good cabinet finish to show off the beauty of the simple modernistic design and veneers .Bad finish and grill cloth , very distracting

13th Apr 2009, 9:06 pm	#1
Ian B Hexode Join Date: May 2006 Location: Arlesey, Bedfordshire, UK. Posts: 401	Murphy A24C I bought a very tatty murphy A24C (console) at a Radiophile auction last year. When I got it home I discovered that things were even worse! It looked like the chassis had been dropped - output valve and rectifier both smashed, one of the smoothing electrolytics bent. Also, the wavechange switch was falling to bits. The switch blades were originally rivetted to the paxolin base with aluminium rivets. An attempt had been made to repair some by soldering (brass to aluminium ?) and another by a small nail with the end bent over (AAgh). Nothing daunted, I thought I'd do a quick bodge-up to see how it really was; the switch contacts are all open on LW, so I could leave that for later. With new reservoir and smoothing electrolytics, and THAT condenser wired in, a U12 and an AC2Pen in place, I powered up. Loads of horrible buzzing, but no tuneable station. Voltage readings on valve bases all good.Thinks - "condenser block", most of the wax caps and a lot of the resistors are inside a tin box under the chassis. Having carefully labelled all the leads before disconnection I checked for resistance readings - all caps very leaky (surprise!). I also found that all the resistors were at least double their correct value. Later that same weekend, refitted condenser block, switched on - exactly the same ! We've gone too far now to give up. So, remove switch assembly, drill out old rivets, remove rusty nail, rivet everything togther firmly and clean contacts. Refit switch, try MW. Five live on top of various other stations in several places Then I noticed that reception was greatly improved if I held the tuning spindle instead of the knob try earthing tuning condenser body - loads of stations loud and clear on both bands. Remove condenser and bracket, tighten screws underneath holding condenser to bracket, refit and replace crumbling connecting wires. Now we're really motoring..... except it won't work below 300m . Try my spare AC TP - no different. Not oscillating, but why. Check voltages on V1, amazed to find it works beautifully when I hold the meter probe on the oscillator grid. Check circuit diagram again, "oscillator grid stabiliser" should be 3K2, measures well over 7K. Replace it with a new 3K3 and HOORAY! Now we'll restuff the (formerly) wet electrolytics to finish the job off properly. What a fantastic sounding set, it's been belting out Pirate Gold all afternoon. The huge speaker gives it plenty of bass without being boomy, and the whole performance is excellent. Now that just leaves the cabinet to do..... I feel I've learned quite a lot from this beast, and certainly had a wet weekend's fun with it. Ian Blackbourn

13th Apr 2009, 9:23 pm	#2
Tazman1966 Nonode Join Date: May 2006 Location: St Albans, Herts, UK. Posts: 2,193	Re: Murphy A24C Hello Ian. I get the feeling that most of us get past a point of no return when starting a restoration and pretty early on too Well done and I look forward to seeing the finished article. Cheers, __________________ All the very best, Tas

14th Apr 2009, 8:41 am	#3
chipp1968 Rest in Peace Join Date: Jul 2006 Location: Somerset, UK. Posts: 2,356	Re: Murphy A24C I think this is the model with rosewood veneer at the top and mahogany lower section and solid light wood contrast between te two . I like murphy console sets . I have this model which was restored proff locally over 10 years ago , yet ive never had it going properly . Now I have a decent aerielearth system I should drag it down .It need s completely stripping and re polishing which is one reason why its upstairs .. cant face it at the mo.This thread is making me think about it which is good .I also have an unrestored A28 as well which needs stripping as well These sortof sets really need good cabinet finish to show off the beauty of the simple modernistic design and veneers .Bad finish and grill cloth , very distracting