Bush EBS31 - valves and locations - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

roberts54 · 7th Dec 2018, 1:55 pm

Many thanks Chris. Which might - might - also suggest if I accidentally swapped ECH42 and EF41 it would not knacker the entire beast.

Excellent. I understand pictures best

That seems spot on, thanks!

My conclusion is:
ECH42 - frequency changer
EF41 - IF amplifier (not EAF41 or EF89)
EBC41 - audio frequency
EZ40 - rectifier (or EZ41)
EL41 - output

Radio Museum seems to be correct thus (assuming it’s ‘spec’). Radio Workshop, understandably lists as ‘found’ - EAF41, EZ41. EZ40 and EZ41 seem interchangeable in this scenario though all the others are '41' so one might think... In any event, my radio def. has an EZ40 rectifier.

Q: My ECH42 and EF41 have no clear markings left and I may have made the classic schoolboy error of swapping them by mistake when cleaning the chassis up. Would this prove fatal for any components?

Thanks again to all - great help and info.

Boater Sam · 7th Dec 2018, 3:08 pm

The set uses the same chassis pressing as the AC31 and DAC31. I am sure that you have the right valves in the right positions.

roberts54 · 7th Dec 2018, 3:21 pm

Thanks Boater Sam, but not if I accidentally swapped them

Nanozeugma's photo illustration is, I believe, correct. Someone sent me the BUSH AC31/DAC31 service instructions which are useful though it only has four valves, not five (ECH42, EBF80, EL41, EZ40 for the AC31).

julie_m · 7th Dec 2018, 3:45 pm

From a quick perusal of the National Valve Museum, swapping over the ECH42 and EF41 is unlikely to have done any lasting harm; it just would not have worked as a radio like that.

roberts54 · 7th Dec 2018, 5:13 pm

Thanks Julie - which gives me some hope. It did manage to pick up one station (plus lots of crackling) prior to my cleaning it in what looked like the first time since 1952. Since then no crackling but no stations. Lights up, as do all valves, and I can hear a purr from the speaker but no Clitheroe Kid or Round the Horne alas

Worth swapping those two valves around then I guess in case I did mess them up.

7th Dec 2018, 1:55 pm	#21
roberts54 Retired Dormant Member Join Date: Dec 2018 Location: Glasgow, Scotland, UK. Posts: 13	Re: Bush EBS31 - valves and locations Many thanks Chris. Which might - might - also suggest if I accidentally swapped ECH42 and EF41 it would not knacker the entire beast. Excellent. I understand pictures best That seems spot on, thanks! My conclusion is: ECH42 - frequency changer EF41 - IF amplifier (not EAF41 or EF89) EBC41 - audio frequency EZ40 - rectifier (or EZ41) EL41 - output Radio Museum seems to be correct thus (assuming it’s ‘spec’). Radio Workshop, understandably lists as ‘found’ - EAF41, EZ41. EZ40 and EZ41 seem interchangeable in this scenario though all the others are '41' so one might think... In any event, my radio def. has an EZ40 rectifier. Q: My ECH42 and EF41 have no clear markings left and I may have made the classic schoolboy error of swapping them by mistake when cleaning the chassis up. Would this prove fatal for any components? Thanks again to all - great help and info.

7th Dec 2018, 3:08 pm	#22
Boater Sam Banned Join Date: Dec 2013 Location: Middlewich, Cheshire, UK. & Winter in the Philippines. Posts: 3,897	Re: Bush EBS31 - valves and locations The set uses the same chassis pressing as the AC31 and DAC31. I am sure that you have the right valves in the right positions.

7th Dec 2018, 3:21 pm	#23
roberts54 Retired Dormant Member Join Date: Dec 2018 Location: Glasgow, Scotland, UK. Posts: 13	Re: Bush EBS31 - valves and locations Thanks Boater Sam, but not if I accidentally swapped them Nanozeugma's photo illustration is, I believe, correct. Someone sent me the BUSH AC31/DAC31 service instructions which are useful though it only has four valves, not five (ECH42, EBF80, EL41, EZ40 for the AC31).

7th Dec 2018, 3:45 pm	#24
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Bush EBS31 - valves and locations From a quick perusal of the National Valve Museum, swapping over the ECH42 and EF41 is unlikely to have done any lasting harm; it just would not have worked as a radio like that. __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

7th Dec 2018, 5:13 pm	#25
roberts54 Retired Dormant Member Join Date: Dec 2018 Location: Glasgow, Scotland, UK. Posts: 13	Re: Bush EBS31 - valves and locations Thanks Julie - which gives me some hope. It did manage to pick up one station (plus lots of crackling) prior to my cleaning it in what looked like the first time since 1952. Since then no crackling but no stations. Lights up, as do all valves, and I can hear a purr from the speaker but no Clitheroe Kid or Round the Horne alas Worth swapping those two valves around then I guess in case I did mess them up.