Bush VHF61, my first restoration attempt. - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Bassette · 26th Jan 2012, 10:47 am

Quote:

Originally Posted by ThePillenwerfer

Good news indeed.

The ECC85 is indeed prime suspect but it could be other things, not least capacitors.

The next thing to do is change THAT capacitor. This is correctly called the AF coupling capacitor and joins the anode of the EABC80 to the grid of the EL84 - top of the EABC80 to the side of the EL84 on the diagram.

This will almost certainly be leaking (electrically if not physically) and if you operate the set for long are putting the EL84 and output transformer at grave risk.

When you've changed that check the voltage on pin 2 of the EL84, hopefully there won't be one!

It would be as well if you told us which service data you are using as different ones use different numbers.

Keep up the good work

Joe

Thank you Joe for this advice I shall print it off and try and locate the numbers on my Bush Service Instructions, as for what sheet number I am working off I draw a blank because I cannot find a number on my reference data.

It would be extremely helpful if you could direct me to the service sheet you work off so as I can study along the same lines you recommend.

My service instructions are poorly reproduced and very difficult to make out.

I hope to pick up the V1 ECC85 valve from a friend in Bath today.

I am beginning to think that my smashed up radio has been such value to me - 2 weeks ago I would have hardly had the nerve to take the back off a set, but the raw chassis
is talking back to me daily guided by many helpful members here.

ThePillenwerfer · 26th Jan 2012, 12:22 pm

The Bush data is better in that the component values are printed on the actual diagram but with it all being on one page it's a bit small. The best thing is to blow it up and print it over several pages. If you want the Trader version you can get it via the link at the top right of the screen - the Bush version is also there and may be clearer than the copy you've got. I've got both versions so we'll stick to the Bush one for now.

THAT capacitor is C56 and is quite easy to get at. It's at the top towards the right on the layout picture on page 3.

As for a VHF aerial, just stick some wire into one of the holes where the internal aerial plugs in.

Cheers

Joe

Station X · 26th Jan 2012, 12:40 pm

I've checked the manufacturer's service sheet as available at top right and it's quite clear when zoomed to 200%.

newlite4 · 26th Jan 2012, 12:51 pm

Terry, I have some VHF61 data ready for you for when you come over later.
Neil

Bassette · 27th Jan 2012, 10:21 am

Well I now have the Trader Sheet 1301 and an unused ECC 85 valve which I relevantly unwrapped thinking deeply about those British hands that made this miracle available as far back as 1956.

Neil, thank you for your support along with others here that are continuing to support this, my new exciting adventure.

I have a few more burning questions awaiting to post here - but it is my Birthday today and I have; not a cake on my kitchen table but a classy Chassis of a Bush VHF 61 - dedication for you!

Terry

Bassette · 27th Jan 2012, 6:58 pm

I need to buy some capacitors now that I have grappled with restoring one to date.

Any suggestions as to a reliable source?

Terry

ThePillenwerfer · 28th Jan 2012, 11:31 am

Mode Components are my usual first choice http://www.modecomponents.co.uk/

- Joe

Bassette · 28th Jan 2012, 2:27 pm

Thanks Joe for the link - I have just changed C65 thinking it was THAT capacitor
but I now note it is C56 5uf what would that convert too in N?

One other point, would you change the two pin power cable and earth the chassis and fit a 3 pin plug?

I note that capacitors come in different voltages would this vary from capacitor to capacitor ?

Freya · 28th Jan 2012, 8:53 pm

5uF would be 5000nF, I think your looking for a 4.7uF maybe?

My sheet shows C56 as 0.01uF and C54 as 0.005uF, which would be replaced with 0.0047uF or 4.7pF.

Steve.

ThePillenwerfer · 28th Jan 2012, 9:08 pm

5uF will be a 4.7uF these days.

It looks like you're using the Trader sheet in which case THAT capacitor is indeed C65, 0.1uF or 100nF.

A microfarrad (uF) is a millionth of a farrad, a nanofarrad (nF) is a thousand-millionth and a picofarrad (pF) is a million-millionth. Therefore 1uF=1,000nF=1,000,000pF.

There are plenty of conversion charts available on the internet.

Hope that helps! Thankfully most old data doesn't use nanofarads.

- Joe

Tim · 30th Jan 2012, 1:24 am

Quote:

which would be replaced with 0.0047uf or 4.7pf.

4700pf

Station X · 30th Jan 2012, 8:43 am

There's a useful conversion chart here which it's worth printing out:-

http://www.justradios.com/uFnFpF.html

Bassette · 30th Jan 2012, 9:56 am

I could do with some guidance as to whether it is necessary to renew the power supply lead with a plug on it because it only has two wires, no earth to go onto the 3 pin plug?

Darren-UK · 30th Jan 2012, 2:38 pm

You're certainly doing the right thing by asking questions but, having said that, you'll learn more by finding the answers to some things for yourself. We could say "Yes you can earth the chassis of such-and-such a radio" or we could say "No, you can't". That would be no good to you though as you need to know why the answer may be "Yes" or "No".

The earthing topic has been flogged to death in the forums but nevertheless I'll give you some clues. So you think you should earth a radio? OK, well ask yourself the following:

a) Does the radio use a mains autotransformer?

b) Does the radio use a mains dropper resistor?

c) Does the radio use a mains isolation transformer and is it for use on AC mains only?

In the case of a) and b) the answer to the earthing question is "No" because the chassis is not isolated from the mains supply. In the case of c) the answer is "Yes, you can earth the chassis".

So what you need to do is determine the answer in respect of the VHF61. Is it for AC mains only and does it use a mains isolating transformer? The types of valve will give a clue; are they E or U series? The circuit diagram will tell you what type of transformer is fitted; have a look and if you're not sure of the symbols then look them up.

On the broad subject of earthing radios, you need to ask yourself one thing. If the radio left the factory decades ago with no earth and has operated like this through the years with no problems, then is earthing really necessary? It's really a matter of personal opinion and a subject I don't wish to kick off yet again here though.

If you determine that the Bush can be earthed and you wish to go ahead and do it, just remember the plug fuse needs to be rated at no more than 3A and the new mains lead should be rated higher than that; for example, 6A lead with a 3A fuse or 3A lead with a 1A or 2A fuse.

Sorry if this post comes across as a bit 'schoolmasterish' but, as said, even though you're doing right by asking questions, you need to determine some answers for yourself and - importantly - understand the reasons for those answers. So I suggest discovering the answers to a), b) and c) then getting back to us before proceeding.

Bassette · 30th Jan 2012, 4:15 pm

Thank you Darren, I am reaching for my glasses as I pen this note.
The answer is c.

Terry

Bassette · 2nd Feb 2012, 1:39 pm

Well, I have raised my head again (been reading a lot).

My stock of capacitors have arrived, so the iron will soon be hot. I will treat each replacement as a single action checking the radio is working every time before moving to replace another, as kindly advised here.

I note that nut spinners my also be something I should acquire for my tool box. I have cutters, long nosed pliers, are there other must have tools that you might like to suggest? We have a Maplins store in Bath.
Terry

Andrewausfa · 2nd Feb 2012, 2:41 pm

Terry,

Assuming you have a basic tool kit plus RCD etc how about these:

Solder sucker.

Buy four medium size insulated croc clips and make up two test leads about foot long. Clip the lead between the connection points of the component/crumbling wire you are about to or just have removed. In essence, a very useful aide-memoire in case you get called away from your work, come back and think "Hmmm, now just where did that resistor connect to". Also handy for various other things.

Useful extra: Head torch for extra lighting in dark and dingy recesses.

Andrew

Bassette · 2nd Feb 2012, 4:54 pm

Hi Andrew,

Yes I have a basic tool kit. My recent electrical interests do not have much influence on my household kit.

Your suggestions are most welcome, I do have the crocodile clips with wire between to short out the capacitors before replacing. Now your suggestion has given them more credence.

Solder sucker, yes now on my list to get.

I have just purchased an Ikea clip-on spot light so this may negate the head light?

Open to any more tips from members.

Terry

Steve_P · 2nd Feb 2012, 5:40 pm

I take it you've got a Multimeter?

How about Flowers and Wine for the other half, to keep her out of your hair.

Cheers,

Steve P.

Bassette · 3rd Feb 2012, 6:54 am

Hi Steve

Yes, I have a multimeter - thank you.

Flowers and wine flow in both directions in my house, as my wife plays Bridge and spends a great deal of time dealing out to friends.

My interests in vintage radios is growing slowly but I am determined to get to grips with the challenge to restore one.

Regards. Terry

26th Jan 2012, 12:22 pm	#22
ThePillenwerfer Octode Join Date: Mar 2011 Location: Sheffield, South Yorkshire, UK. Posts: 1,453	Re: Bush VHF61, my first restoration attempt. The Bush data is better in that the component values are printed on the actual diagram but with it all being on one page it's a bit small. The best thing is to blow it up and print it over several pages. If you want the Trader version you can get it via the link at the top right of the screen - the Bush version is also there and may be clearer than the copy you've got. I've got both versions so we'll stick to the Bush one for now. THAT capacitor is C56 and is quite easy to get at. It's at the top towards the right on the layout picture on page 3. As for a VHF aerial, just stick some wire into one of the holes where the internal aerial plugs in. Cheers Joe __________________ "Experts are only good at one thing: explaining why something will not work!"

26th Jan 2012, 12:40 pm	#23
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Bush VHF61, my first restoration attempt. I've checked the manufacturer's service sheet as available at top right and it's quite clear when zoomed to 200%. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

26th Jan 2012, 12:51 pm	#24
newlite4 Octode Join Date: Nov 2003 Location: Bath, Somerset, UK. Posts: 1,805	Re: Bush VHF61, my first restoration attempt. Terry, I have some VHF61 data ready for you for when you come over later. Neil __________________ preserving the recent past, for the distant future.

27th Jan 2012, 10:21 am	#25
Bassette Retired Dormant Member Join Date: Dec 2011 Location: Bath Posts: 49	Re: Bush VHF61, my first restoration attempt. Well I now have the Trader Sheet 1301 and an unused ECC 85 valve which I relevantly unwrapped thinking deeply about those British hands that made this miracle available as far back as 1956. Neil, thank you for your support along with others here that are continuing to support this, my new exciting adventure. I have a few more burning questions awaiting to post here - but it is my Birthday today and I have; not a cake on my kitchen table but a classy Chassis of a Bush VHF 61 - dedication for you! Terry

27th Jan 2012, 6:58 pm	#26
Bassette Retired Dormant Member Join Date: Dec 2011 Location: Bath Posts: 49	Re: Bush VHF61, my first restoration attempt. I need to buy some capacitors now that I have grappled with restoring one to date. Any suggestions as to a reliable source? Terry

28th Jan 2012, 11:31 am	#27
ThePillenwerfer Octode Join Date: Mar 2011 Location: Sheffield, South Yorkshire, UK. Posts: 1,453	Re: Bush VHF61, my first restoration attempt. Mode Components are my usual first choice http://www.modecomponents.co.uk/ - Joe __________________ "Experts are only good at one thing: explaining why something will not work!"

28th Jan 2012, 2:27 pm	#28
Bassette Retired Dormant Member Join Date: Dec 2011 Location: Bath Posts: 49	Re: Bush VHF61, my first restoration attempt. Thanks Joe for the link - I have just changed C65 thinking it was THAT capacitor but I now note it is C56 5uf what would that convert too in N? One other point, would you change the two pin power cable and earth the chassis and fit a 3 pin plug? I note that capacitors come in different voltages would this vary from capacitor to capacitor ?

28th Jan 2012, 8:53 pm	#29
Freya Octode Join Date: Jan 2009 Location: Falmouth, Cornwall, UK. Posts: 1,990	Re: Bush VHF61, my first restoration attempt. 5uF would be 5000nF, I think your looking for a 4.7uF maybe? My sheet shows C56 as 0.01uF and C54 as 0.005uF, which would be replaced with 0.0047uF or 4.7pF. Steve. Last edited by Freya; 28th Jan 2012 at 9:01 pm.

28th Jan 2012, 9:08 pm	#30
ThePillenwerfer Octode Join Date: Mar 2011 Location: Sheffield, South Yorkshire, UK. Posts: 1,453	Re: Bush VHF61, my first restoration attempt. 5uF will be a 4.7uF these days. It looks like you're using the Trader sheet in which case THAT capacitor is indeed C65, 0.1uF or 100nF. A microfarrad (uF) is a millionth of a farrad, a nanofarrad (nF) is a thousand-millionth and a picofarrad (pF) is a million-millionth. Therefore 1uF=1,000nF=1,000,000pF. There are plenty of conversion charts available on the internet. Hope that helps! Thankfully most old data doesn't use nanofarads. - Joe __________________ "Experts are only good at one thing: explaining why something will not work!"

30th Jan 2012, 8:43 am	#32
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Bush VHF61, my first restoration attempt. There's a useful conversion chart here which it's worth printing out:- http://www.justradios.com/uFnFpF.html __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

30th Jan 2012, 9:56 am	#33
Bassette Retired Dormant Member Join Date: Dec 2011 Location: Bath Posts: 49	Re: Bush VHF61, my first restoration attempt. I could do with some guidance as to whether it is necessary to renew the power supply lead with a plug on it because it only has two wires, no earth to go onto the 3 pin plug?

30th Jan 2012, 2:38 pm	#34
Darren-UK Retired Dormant Member Join Date: Apr 2003 Location: Blackpool, Lancashire, UK. Posts: 4,061	Re: Bush VHF61, my first restoration attempt. You're certainly doing the right thing by asking questions but, having said that, you'll learn more by finding the answers to some things for yourself. We could say "Yes you can earth the chassis of such-and-such a radio" or we could say "No, you can't". That would be no good to you though as you need to know why the answer may be "Yes" or "No". The earthing topic has been flogged to death in the forums but nevertheless I'll give you some clues. So you think you should earth a radio? OK, well ask yourself the following: a) Does the radio use a mains autotransformer? b) Does the radio use a mains dropper resistor? c) Does the radio use a mains isolation transformer and is it for use on AC mains only? In the case of a) and b) the answer to the earthing question is "No" because the chassis is not isolated from the mains supply. In the case of c) the answer is "Yes, you can earth the chassis". So what you need to do is determine the answer in respect of the VHF61. Is it for AC mains only and does it use a mains isolating transformer? The types of valve will give a clue; are they E or U series? The circuit diagram will tell you what type of transformer is fitted; have a look and if you're not sure of the symbols then look them up. On the broad subject of earthing radios, you need to ask yourself one thing. If the radio left the factory decades ago with no earth and has operated like this through the years with no problems, then is earthing really necessary? It's really a matter of personal opinion and a subject I don't wish to kick off yet again here though. If you determine that the Bush can be earthed and you wish to go ahead and do it, just remember the plug fuse needs to be rated at no more than 3A and the new mains lead should be rated higher than that; for example, 6A lead with a 3A fuse or 3A lead with a 1A or 2A fuse. Sorry if this post comes across as a bit 'schoolmasterish' but, as said, even though you're doing right by asking questions, you need to determine some answers for yourself and - importantly - understand the reasons for those answers. So I suggest discovering the answers to a), b) and c) then getting back to us before proceeding.

30th Jan 2012, 4:15 pm	#35
Bassette Retired Dormant Member Join Date: Dec 2011 Location: Bath Posts: 49	Re: Bush VHF61, my first restoration attempt. Thank you Darren, I am reaching for my glasses as I pen this note. The answer is c. Terry

2nd Feb 2012, 1:39 pm	#36
Bassette Retired Dormant Member Join Date: Dec 2011 Location: Bath Posts: 49	Re: Bush VHF61, my first restoration attempt. Well, I have raised my head again (been reading a lot). My stock of capacitors have arrived, so the iron will soon be hot. I will treat each replacement as a single action checking the radio is working every time before moving to replace another, as kindly advised here. I note that nut spinners my also be something I should acquire for my tool box. I have cutters, long nosed pliers, are there other must have tools that you might like to suggest? We have a Maplins store in Bath. Terry

2nd Feb 2012, 2:41 pm	#37
Andrewausfa Octode Join Date: Dec 2010 Location: St Ives, Cambridgeshire, UK. Posts: 1,180	Re: Bush VHF61, my first restoration attempt. Terry, Assuming you have a basic tool kit plus RCD etc how about these: Solder sucker. Buy four medium size insulated croc clips and make up two test leads about foot long. Clip the lead between the connection points of the component/crumbling wire you are about to or just have removed. In essence, a very useful aide-memoire in case you get called away from your work, come back and think "Hmmm, now just where did that resistor connect to". Also handy for various other things. Useful extra: Head torch for extra lighting in dark and dingy recesses. Andrew __________________ Invisible airwaves crackle with life. Or they should do. BVWS Member

2nd Feb 2012, 4:54 pm	#38
Bassette Retired Dormant Member Join Date: Dec 2011 Location: Bath Posts: 49	Re: Bush VHF61, my first restoration attempt. Hi Andrew, Yes I have a basic tool kit. My recent electrical interests do not have much influence on my household kit. Your suggestions are most welcome, I do have the crocodile clips with wire between to short out the capacitors before replacing. Now your suggestion has given them more credence. Solder sucker, yes now on my list to get. I have just purchased an Ikea clip-on spot light so this may negate the head light? Open to any more tips from members. Terry

2nd Feb 2012, 5:40 pm	#39
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Bush VHF61, my first restoration attempt. I take it you've got a Multimeter? How about Flowers and Wine for the other half, to keep her out of your hair. Cheers, Steve P. __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

3rd Feb 2012, 6:54 am	#40
Bassette Retired Dormant Member Join Date: Dec 2011 Location: Bath Posts: 49	Re: Bush VHF61, my first restoration attempt. Hi Steve Yes, I have a multimeter - thank you. Flowers and wine flow in both directions in my house, as my wife plays Bridge and spends a great deal of time dealing out to friends. My interests in vintage radios is growing slowly but I am determined to get to grips with the challenge to restore one. Regards. Terry