Bush VHF62 tuning problem - UK Vintage Radio Repair and Restoration Discussion Forum

barryman · 22nd Mar 2021, 1:19 pm

I'm trying to link up an FM transmitter and pick the signal up on the VHF band of this Bush VHF 62. Thanks to advice I got on this form I was about to order an FM transmitter that somebody suggested would achieve what I wanted to do. As a final check I tested the VHF band by going up the scale from left to right. Unfortunately when I got to the top end of the scale the the tuning knob just went into free spin and the tuning indicator stayed in one place ! I guessed that something has come loose inside.

I'm not a radio engineer myself but I thought if it was something
mechanical I might be able to fix it so I took off the back and I think I
can see the problem. The cord that should go round various pulleys to move the tuner seems to have come off its groove but I can't work out how I loop it back over the pulleys - there seems to be no slack in the cord to stretch it back round.

Could anyone give me any tips on how I can do this myself? Failing that, is
there anybody within shouting distance of Watford who would be so kind as to help me do this 5 minute fix if I brought it round??

Any advice on how I can do the above will be greatly appreciated as this is a lovely radio and I want to keep it working.
[/LEFT]
Thanks in advance.

coopzone · 22nd Mar 2021, 1:29 pm

They are a bit tricky, the slack is the "sping" you see on top of the large round spindle. You need to be carful not to stretch it to much, but it should provide enough give to put the chrord back on. They are fairly tight, but not piano wire tight! Attached is a diagram from the service sheet. Just go slow and steady.

coopzone · 23rd Mar 2021, 10:48 am

Barryman replied with:

Hi and thanks so much for responding to my post.
I have seen the diagram you sent but I am not having any joy yet with getting the cord back to where it should be ! I presume when you say "large round spindle" you obviously mean the big 4" disc at the top of the radio. I cannot see how to get any movement in it. There is a small spring on the wheel but I can't seem to make the wheel slacker in any way to get the cord back round it. Or is there another pulley that is on a spring?

What am I doing wrong ??

coopzone · 23rd Mar 2021, 10:56 am

I was referring to the third photo in your first post. Unless something is very wrong that large flat disc connects directly to the tuning capacitor, the mechanism directly below it. It should move, even if it is restricted by the cord thats come of it. You should be able to move it freely and see the vanes move bellow it.

If not, then the only thing i can think of is one of the vanes has somehow broken and is stuck ? Or perhaps the bearing on the capacitor has collapsed - not very likely .

Either way - if it really is stuck, then the cord coming off is a consequence of a bigger issue not the cause. It may well need that part removing and stripping down or replacing. A bigger job.

Worth getting someone to take a look for you, it's a nice radio. And that one looks nice and clean.

Try an add in the wanted section?

Gabe001 · 23rd Mar 2021, 3:53 pm

Dealing with dial strings can be a bit tricky, but unless it's got undone somewhere else all you need to do is pull the string so that it fits again in the groove on the "disc". If you have some tweezers they work as levers, just be careful not to damage the cord.

barryman · 23rd Mar 2021, 5:57 pm

Thanks to the advice from Coopzone I have managed to free up the cord that wraps around the pulleys etc. Now that I have done that I am a bit stuck about actually rethreading it.

Firstly, which end do I start with - the large spindle plate or do I feed cord around the small pulleys first ? The cord is coming from the right hand side. It's all hanging loose at the moment and I know I will need to reattach the spring onto the spindle plate but is that the first or final thing to do? I have got the diagram as sent to me but you knowledgeable people will know what is the best practical way to rethread it.

Thanks for any advice you can give me.

coopzone · 23rd Mar 2021, 6:23 pm

I normally start with the small ones and leave the larger one till last that - to me - seems to lesson the "stress" needed on the cord that way. But it's probably fair to say " trial and error". Just try not to put to much pressure on the cord.

barryman · 24th Mar 2021, 1:12 pm

Well, I spent hours yesterday trying to loop the cord as the diagram shows. I am pretty certain that it would be easier if I can remove the chassis so that I can access all the pulleys etc from the front. So, how does the chassis on a Bush VHF62 come out ?? - I can't see any obvious retaining screws etc. Or is there any way or tips to rethread cord from the back end without removing chassis??

coopzone · 24th Mar 2021, 1:24 pm

So it looks like your slowly being drawn in. No way back you know. You will soon be visiting car boot sales (covid permitting) for your next project.

Attached is an extract from the service sheet giving details of how to remove the chassis. Only go as far as you need, take photos as you go to help remember where things go. You probably don't need to do more than pull in back a bit in truth. Good luck.

Derek

barryman · 24th Mar 2021, 2:09 pm

Oh my goodness, this is something I dreaded having to attempt. I just had a cursory look and can see 4 bolts on the underside. However, there are no retaining bolts I can see from the chassis to the inside walls of the cabinet.

Also, if I did eventually get the chassis to slide out I presume I have to disconnect speaker wires etc. That's probably not a problem. However, if just the chassis comes out will it have the complete gubbins including all the tuning mechanism that connects to the vertical tuning indicator enabling me to completely rethread ready to be pushed back into cabinet ?? Just looking with my untrained eyes it just looks like pulling the chassis out will pull the cord with it but that would need to connect with the tuning dial knob, no?? Maybe I'm wrong....

coopzone · 24th Mar 2021, 6:20 pm

The VHF62 is a wooden cab version of the VHF61, the service sheet covers both so it's possible the side screws a slightly different.

As I remember (it's been a while since i last looked inside my radio) the chassis pulls out and brings with it all the front glass and dials etc with it. Yes you may need to undo the speaker - it should be screwed terminals on the output transformer.

You may need to undo the tuning indicator. But hopefully not. try not to. You may have just enough room to twist the chassis round 90' to give access to the pulleys either end of the scale etc.

The Tuning indicator valve has a valve base on the end of a flexible set of cables. You may be lucky and be able to remove it from the valve, but if possible it's safer bet to remove any clips from around the valve. For many reasons. Not least of them being the cables are rubber covered and it tends to perish while it's not moving it's ok, but as soon as you disturb it it may fall apart.

Derek

barryman · 24th Mar 2021, 8:35 pm

Thanks Derek - I'll try my luck on doing in the next few days. Many thanks for your advice so far. Obviously, I'll let you know if I manage to do it !

Barry

barryman · 25th Mar 2021, 12:04 pm

Glad to say I'm well on the way thanks to brilliant advice received. I've now got the chassis out and have attached photos taken from the front, giving me full access. It's the last few steps that I need help on.

From the diagram you sent me I can see the "route" that the cord should take. But I can't quite work out where and how it attaches to the large disc. Given that I have the cord coming from two directions ie from round the tuning knob spindle and also from the lowest end of the scale, I'm not sure how to route both cords around the disc. I know it has to sit in the notch cut into the rim of the disc and I currently have the spring unclipped. Also the tuning indicator is currently at the top end of the scale (105 VHF) as this is how it appears in the diagram.

So, what is the correct way to do the final placement of the cord around the disc

coopzone · 25th Mar 2021, 5:29 pm

Ok, you see from your photo that the highest two small white plastic guides, tops, line up with the horizontal disc on top of the tuning capacitor? These are shown on the diagram I sent as the top two small guides. As pic1a and pic2a attached.

Look closely at the diagram and position the "cursor" to the right of the tuning dial and the large disc to the same position shown. It should be fully turned in one direction.

With luck, the string that comes from the left will be shorter that the one from the right, it goes across the front grove on the disc, enters the disc through the hole in the side by the letter L on the diagram. then attach the spring.

Next the one from the right will go above the left one, round the disc and into the rear part of the hole - where it should be held tight by the spring.

Make sure the other white plastic guides are correct. Considering the cord was never removed / replaced they should be ok, and the position of the cursor, number of turns etc on the control spindle will all be ok.

go slow, keep referring to the diagram.

Derek

barryman · 26th Mar 2021, 12:53 pm

I have followed instructions and I can't be far away from the finishing line !! It's the last bit that I cannot work out.

If you look at my attached marked-up diagram and the photos you will see the route the cord is taking. I'm sure I have followed the diagram carefully. Where I am having trouble is with running the cords around the big disc D.

Is the cord coming off pulley C meant to go round the disk D clockwise to the right or anti-clockwise to the left? Also, I presume the cord from pulley E runs clockwise round A to the left?

What I am finding is that, so far, I cannot get the cord to give enough slack for me to locate the spring onto the little lug on A I cannot get it's cutout notch round enough to feed in the cord. What am I doing wrong ??

Barry

ms660 · 26th Mar 2021, 1:39 pm

Looking at the diagram you first need to ascertain which length of cord is which that's attached to the spring, the length you need to start off with is the length that is towards the rear of the tuning spindle once that's established then place the spring in the drum so that the cord ends are near the slot and route the said length clockwise round drum D for a bit then route it via pullies C, B, A, the cursor and finally F all as shown in the diagram, if there is any slack in the cord between pully F and the tuning spindle then you need to get rid of the slack, that can be done by pulling on the length of cord that is towards the front of the tuning spindle, you might have to help/jiggle it around the spindle with your finger or something while turning the spindle clockwise, once you're satisfied that there is no slack then route the cord that's towards the front of the spindle over pully E then clockwise round drum D to the slot then attach the spring to it's anchor point, then do a tuning run in both directions for a time or two to settle everything in.

Lawrence.

barryman · 26th Mar 2021, 2:38 pm

I'm a bit confused, Lawrence, - both ends of the cord are joined up to the spring that sits on the tuning wheel D The wheel D only moves a certain amount in each direction to align the notch. In which case, are you saying that I need to start at the wheel end, ie. attaching spring first and then feeding cords back from that to try to route the rest of the cord around all the other pulley wheels?

The cord is complete - nothing snapped - it obviously just came off it's pulleys for some reason. I think I am also getting a bit unhinged by this !!

ms660 · 26th Mar 2021, 2:51 pm

Quote:

Originally Posted by barryman

I'm a bit confused, Lawrence, - both ends of the cord are joined up to the spring that sits on the tuning wheel D

Yes that's right, two cord ends at the spring, you want to start with length that's attached to the spring and is also the rearmost on the tuning spindle, hooking the spring to its anchor point is the last operation, the cord route in the diagram is self explanatory.

Lawrence.

barryman · 26th Mar 2021, 4:55 pm

So, just so I am absolutely clear, (as the diagram is not particularly clear), the cord coming off the pulley marked C goes which way around the tuning disc D ?? And the cord coming off pulley E goes which way? Currently I am trying to feed the cord from pulley E around the left of the wheel (clockwise) and the cord from pulley C around to the right of the disc (anti clockwise). This is where it's all going wrong for me as there does not seem to be enough slack in the cord to get BOTH sides of the cord through the little entrance notch on the side of D in order to reattach the spring.

Ta

ms660 · 26th Mar 2021, 5:17 pm

According to the diagram the cord coming off pulley C goes anti-clockwise round pulley D to the slot, the cord coming off pulley E goes clockwise round Pulley D to the slot. Make sure there aren't too many turns round the tuning spindle, it says four and a half turns in the diagram but it might have originally been configured with less turns but I wouldn't know for sure.

Lawrence.

22nd Mar 2021, 1:19 pm	#1
barryman Triode Join Date: Jul 2006 Location: Bushey, Herts, UK. Posts: 26	Bush VHF62 tuning problem I'm trying to link up an FM transmitter and pick the signal up on the VHF band of this Bush VHF 62. Thanks to advice I got on this form I was about to order an FM transmitter that somebody suggested would achieve what I wanted to do. As a final check I tested the VHF band by going up the scale from left to right. Unfortunately when I got to the top end of the scale the the tuning knob just went into free spin and the tuning indicator stayed in one place ! I guessed that something has come loose inside. I'm not a radio engineer myself but I thought if it was something mechanical I might be able to fix it so I took off the back and I think I can see the problem. The cord that should go round various pulleys to move the tuner seems to have come off its groove but I can't work out how I loop it back over the pulleys - there seems to be no slack in the cord to stretch it back round. Could anyone give me any tips on how I can do this myself? Failing that, is there anybody within shouting distance of Watford who would be so kind as to help me do this 5 minute fix if I brought it round?? Any advice on how I can do the above will be greatly appreciated as this is a lovely radio and I want to keep it working. [/LEFT] Thanks in advance. Attached Thumbnails

22nd Mar 2021, 1:29 pm	#2
coopzone Hexode Join Date: Jan 2018 Location: Cannock, Staffordshire, UK. Posts: 268	Re: Bush VHF62 tuning problem They are a bit tricky, the slack is the "sping" you see on top of the large round spindle. You need to be carful not to stretch it to much, but it should provide enough give to put the chrord back on. They are fairly tight, but not piano wire tight! Attached is a diagram from the service sheet. Just go slow and steady. Attached Thumbnails

23rd Mar 2021, 10:48 am	#3
coopzone Hexode Join Date: Jan 2018 Location: Cannock, Staffordshire, UK. Posts: 268	Re: Bush VHF62 tuning problem Barryman replied with: Hi and thanks so much for responding to my post. I have seen the diagram you sent but I am not having any joy yet with getting the cord back to where it should be ! I presume when you say "large round spindle" you obviously mean the big 4" disc at the top of the radio. I cannot see how to get any movement in it. There is a small spring on the wheel but I can't seem to make the wheel slacker in any way to get the cord back round it. Or is there another pulley that is on a spring? What am I doing wrong ??

23rd Mar 2021, 10:56 am	#4
coopzone Hexode Join Date: Jan 2018 Location: Cannock, Staffordshire, UK. Posts: 268	Re: Bush VHF62 tuning problem I was referring to the third photo in your first post. Unless something is very wrong that large flat disc connects directly to the tuning capacitor, the mechanism directly below it. It should move, even if it is restricted by the cord thats come of it. You should be able to move it freely and see the vanes move bellow it. If not, then the only thing i can think of is one of the vanes has somehow broken and is stuck ? Or perhaps the bearing on the capacitor has collapsed - not very likely . Either way - if it really is stuck, then the cord coming off is a consequence of a bigger issue not the cause. It may well need that part removing and stripping down or replacing. A bigger job. Worth getting someone to take a look for you, it's a nice radio. And that one looks nice and clean. Try an add in the wanted section?

23rd Mar 2021, 3:53 pm	#5
Gabe001 Octode Join Date: Oct 2019 Location: Stockport, Greater Manchester, UK. Posts: 1,646	Re: Bush VHF62 tuning problem Dealing with dial strings can be a bit tricky, but unless it's got undone somewhere else all you need to do is pull the string so that it fits again in the groove on the "disc". If you have some tweezers they work as levers, just be careful not to damage the cord.

23rd Mar 2021, 5:57 pm	#6
barryman Triode Join Date: Jul 2006 Location: Bushey, Herts, UK. Posts: 26	Re: Bush VHF62 tuning problem Thanks to the advice from Coopzone I have managed to free up the cord that wraps around the pulleys etc. Now that I have done that I am a bit stuck about actually rethreading it. Firstly, which end do I start with - the large spindle plate or do I feed cord around the small pulleys first ? The cord is coming from the right hand side. It's all hanging loose at the moment and I know I will need to reattach the spring onto the spindle plate but is that the first or final thing to do? I have got the diagram as sent to me but you knowledgeable people will know what is the best practical way to rethread it. Thanks for any advice you can give me. Attached Thumbnails

23rd Mar 2021, 6:23 pm	#7
coopzone Hexode Join Date: Jan 2018 Location: Cannock, Staffordshire, UK. Posts: 268	Re: Bush VHF62 tuning problem I normally start with the small ones and leave the larger one till last that - to me - seems to lesson the "stress" needed on the cord that way. But it's probably fair to say " trial and error". Just try not to put to much pressure on the cord.

24th Mar 2021, 1:12 pm	#8
barryman Triode Join Date: Jul 2006 Location: Bushey, Herts, UK. Posts: 26	Re: Bush VHF62 tuning problem Well, I spent hours yesterday trying to loop the cord as the diagram shows. I am pretty certain that it would be easier if I can remove the chassis so that I can access all the pulleys etc from the front. So, how does the chassis on a Bush VHF62 come out ?? - I can't see any obvious retaining screws etc. Or is there any way or tips to rethread cord from the back end without removing chassis?? Last edited by barryman; 24th Mar 2021 at 1:20 pm.

24th Mar 2021, 1:24 pm	#9
coopzone Hexode Join Date: Jan 2018 Location: Cannock, Staffordshire, UK. Posts: 268	Re: Bush VHF62 tuning problem So it looks like your slowly being drawn in. No way back you know. You will soon be visiting car boot sales (covid permitting) for your next project. Attached is an extract from the service sheet giving details of how to remove the chassis. Only go as far as you need, take photos as you go to help remember where things go. You probably don't need to do more than pull in back a bit in truth. Good luck. Derek Attached Thumbnails

24th Mar 2021, 2:09 pm	#10
barryman Triode Join Date: Jul 2006 Location: Bushey, Herts, UK. Posts: 26	Re: Bush VHF62 tuning problem Oh my goodness, this is something I dreaded having to attempt. I just had a cursory look and can see 4 bolts on the underside. However, there are no retaining bolts I can see from the chassis to the inside walls of the cabinet. Also, if I did eventually get the chassis to slide out I presume I have to disconnect speaker wires etc. That's probably not a problem. However, if just the chassis comes out will it have the complete gubbins including all the tuning mechanism that connects to the vertical tuning indicator enabling me to completely rethread ready to be pushed back into cabinet ?? Just looking with my untrained eyes it just looks like pulling the chassis out will pull the cord with it but that would need to connect with the tuning dial knob, no?? Maybe I'm wrong....

24th Mar 2021, 6:20 pm	#11
coopzone Hexode Join Date: Jan 2018 Location: Cannock, Staffordshire, UK. Posts: 268	Re: Bush VHF62 tuning problem The VHF62 is a wooden cab version of the VHF61, the service sheet covers both so it's possible the side screws a slightly different. As I remember (it's been a while since i last looked inside my radio) the chassis pulls out and brings with it all the front glass and dials etc with it. Yes you may need to undo the speaker - it should be screwed terminals on the output transformer. You may need to undo the tuning indicator. But hopefully not. try not to. You may have just enough room to twist the chassis round 90' to give access to the pulleys either end of the scale etc. The Tuning indicator valve has a valve base on the end of a flexible set of cables. You may be lucky and be able to remove it from the valve, but if possible it's safer bet to remove any clips from around the valve. For many reasons. Not least of them being the cables are rubber covered and it tends to perish while it's not moving it's ok, but as soon as you disturb it it may fall apart. Derek

24th Mar 2021, 8:35 pm	#12
barryman Triode Join Date: Jul 2006 Location: Bushey, Herts, UK. Posts: 26	Re: Bush VHF62 tuning problem Thanks Derek - I'll try my luck on doing in the next few days. Many thanks for your advice so far. Obviously, I'll let you know if I manage to do it ! Barry

25th Mar 2021, 12:04 pm	#13
barryman Triode Join Date: Jul 2006 Location: Bushey, Herts, UK. Posts: 26	Re: Bush VHF62 tuning problem Glad to say I'm well on the way thanks to brilliant advice received. I've now got the chassis out and have attached photos taken from the front, giving me full access. It's the last few steps that I need help on. From the diagram you sent me I can see the "route" that the cord should take. But I can't quite work out where and how it attaches to the large disc. Given that I have the cord coming from two directions ie from round the tuning knob spindle and also from the lowest end of the scale, I'm not sure how to route both cords around the disc. I know it has to sit in the notch cut into the rim of the disc and I currently have the spring unclipped. Also the tuning indicator is currently at the top end of the scale (105 VHF) as this is how it appears in the diagram. So, what is the correct way to do the final placement of the cord around the disc Attached Thumbnails

25th Mar 2021, 5:29 pm	#14
coopzone Hexode Join Date: Jan 2018 Location: Cannock, Staffordshire, UK. Posts: 268	Re: Bush VHF62 tuning problem Ok, you see from your photo that the highest two small white plastic guides, tops, line up with the horizontal disc on top of the tuning capacitor? These are shown on the diagram I sent as the top two small guides. As pic1a and pic2a attached. Look closely at the diagram and position the "cursor" to the right of the tuning dial and the large disc to the same position shown. It should be fully turned in one direction. With luck, the string that comes from the left will be shorter that the one from the right, it goes across the front grove on the disc, enters the disc through the hole in the side by the letter L on the diagram. then attach the spring. Next the one from the right will go above the left one, round the disc and into the rear part of the hole - where it should be held tight by the spring. Make sure the other white plastic guides are correct. Considering the cord was never removed / replaced they should be ok, and the position of the cursor, number of turns etc on the control spindle will all be ok. go slow, keep referring to the diagram. Derek Attached Thumbnails

26th Mar 2021, 12:53 pm	#15
barryman Triode Join Date: Jul 2006 Location: Bushey, Herts, UK. Posts: 26	Re: Bush VHF62 tuning problem I have followed instructions and I can't be far away from the finishing line !! It's the last bit that I cannot work out. If you look at my attached marked-up diagram and the photos you will see the route the cord is taking. I'm sure I have followed the diagram carefully. Where I am having trouble is with running the cords around the big disc D. Is the cord coming off pulley C meant to go round the disk D clockwise to the right or anti-clockwise to the left? Also, I presume the cord from pulley E runs clockwise round A to the left? What I am finding is that, so far, I cannot get the cord to give enough slack for me to locate the spring onto the little lug on A I cannot get it's cutout notch round enough to feed in the cord. What am I doing wrong ?? Barry Attached Thumbnails

26th Mar 2021, 1:39 pm	#16
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Bush VHF62 tuning problem Looking at the diagram you first need to ascertain which length of cord is which that's attached to the spring, the length you need to start off with is the length that is towards the rear of the tuning spindle once that's established then place the spring in the drum so that the cord ends are near the slot and route the said length clockwise round drum D for a bit then route it via pullies C, B, A, the cursor and finally F all as shown in the diagram, if there is any slack in the cord between pully F and the tuning spindle then you need to get rid of the slack, that can be done by pulling on the length of cord that is towards the front of the tuning spindle, you might have to help/jiggle it around the spindle with your finger or something while turning the spindle clockwise, once you're satisfied that there is no slack then route the cord that's towards the front of the spindle over pully E then clockwise round drum D to the slot then attach the spring to it's anchor point, then do a tuning run in both directions for a time or two to settle everything in. Lawrence. Last edited by ms660; 26th Mar 2021 at 1:45 pm.

26th Mar 2021, 2:38 pm	#17
barryman Triode Join Date: Jul 2006 Location: Bushey, Herts, UK. Posts: 26	Re: Bush VHF62 tuning problem I'm a bit confused, Lawrence, - both ends of the cord are joined up to the spring that sits on the tuning wheel D The wheel D only moves a certain amount in each direction to align the notch. In which case, are you saying that I need to start at the wheel end, ie. attaching spring first and then feeding cords back from that to try to route the rest of the cord around all the other pulley wheels? The cord is complete - nothing snapped - it obviously just came off it's pulleys for some reason. I think I am also getting a bit unhinged by this !!

26th Mar 2021, 4:55 pm	#19
barryman Triode Join Date: Jul 2006 Location: Bushey, Herts, UK. Posts: 26	Re: Bush VHF62 tuning problem So, just so I am absolutely clear, (as the diagram is not particularly clear), the cord coming off the pulley marked C goes which way around the tuning disc D ?? And the cord coming off pulley E goes which way? Currently I am trying to feed the cord from pulley E around the left of the wheel (clockwise) and the cord from pulley C around to the right of the disc (anti clockwise). This is where it's all going wrong for me as there does not seem to be enough slack in the cord to get BOTH sides of the cord through the little entrance notch on the side of D in order to reattach the spring. Ta

26th Mar 2021, 5:17 pm	#20
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Bush VHF62 tuning problem According to the diagram the cord coming off pulley C goes anti-clockwise round pulley D to the slot, the cord coming off pulley E goes clockwise round Pulley D to the slot. Make sure there aren't too many turns round the tuning spindle, it says four and a half turns in the diagram but it might have originally been configured with less turns but I wouldn't know for sure. Lawrence.