Avo HF135 Access - UK Vintage Radio Repair and Restoration Discussion Forum

twizzle · 1st Jul 2019, 6:56 pm

Hi all.

Anyone know how to take one of these units apart? There are a number of screws on the rear and I suspect not all would open the case. There are also ones on the front, again not sure which would open the case and of course all the knobs on the front. Knobs will not budge although I've used very little force, front screws make no difference and neither do the rear ones. Result, I'm stuck. Clearly so is the case but without having precise knowledge of the sequence of disassembly I'm not going to go further. Can anyone enlighten me? Once I know I've undone the correct fixings and it SHOULD come apart I can go at it with more confidence. Right now it's a Chinese puzzle. Many thanks in advance.

wd40addict · 2nd Jul 2019, 7:01 pm

As far as I remember you just undo the four big bolts on the front panel and it lifts out.

twizzle · 2nd Jul 2019, 8:29 pm

Yes, you'd think so but it won't budge. Is it supposed to come out with all the front panel knobs/controls in place? Or, do the knobs come off and leave spindles/pots in place after removing any shaft nuts? A bit like 70's Pioneer HiFi when taking the front plate off. Either way, the knobs are stuck on and I can't even work out if these are push on with a spring clip or whether they are collet type. It looks like the top of the knob comes off to reveal a collet nut but that won't shift either. What a nightmare...

wd40addict · 2nd Jul 2019, 9:00 pm

You definitely don't need to remove knobs. I'm afraid I can't check my unit at the moment to see if there's anything else that needs removing.

Stockden · 3rd Jul 2019, 7:36 am

It's a very long time since I played with one of these but I seem to recall that you also have to remove the 2 screws towards the middle of the back panel (i.e. the 2 that aren't round the edge).

If I remember correctly these secure the back panel to the coil box and so stop the whole lot moving forwards.

Hugh

micheal · 3rd Jul 2019, 12:04 pm

As Stocken said remove two screws in centre of back.
you do not need to remove knobs,but if at any time you do need to remove knobs pull top cap of knob with finger nail to reveal a collet nut be hind, i think it might be 7 or 8mm.

Mike

twizzle · 5th Jul 2019, 10:29 pm

Thanks guys. I think the key to the puzzle is the x2 screws at the back that have been mentioned. That's not a combination I tried plus the front screws so I'm hopeful that'll sort it. I could feel the front panel held from moving in a way that was probably consistent with those rogue screws in place! As I said in my initial question, there's a combination to unlock the box somewhere and I didn't want to start shotgunning fixings if someone out there could provide the combination. I'll try it this weekend. Many thanks.

1st Jul 2019, 6:56 pm	#1
twizzle Triode Join Date: Feb 2017 Location: Bradford, West Yorkshire, UK. Posts: 12	Avo HF135 Access Hi all. Anyone know how to take one of these units apart? There are a number of screws on the rear and I suspect not all would open the case. There are also ones on the front, again not sure which would open the case and of course all the knobs on the front. Knobs will not budge although I've used very little force, front screws make no difference and neither do the rear ones. Result, I'm stuck. Clearly so is the case but without having precise knowledge of the sequence of disassembly I'm not going to go further. Can anyone enlighten me? Once I know I've undone the correct fixings and it SHOULD come apart I can go at it with more confidence. Right now it's a Chinese puzzle. Many thanks in advance.

2nd Jul 2019, 7:01 pm	#2
wd40addict Octode Join Date: May 2009 Location: Stevenage, Herts. UK. Posts: 1,518	Re: Avo HF135 Access As far as I remember you just undo the four big bolts on the front panel and it lifts out.

2nd Jul 2019, 8:29 pm	#3
twizzle Triode Join Date: Feb 2017 Location: Bradford, West Yorkshire, UK. Posts: 12	Re: Avo HF135 Access Yes, you'd think so but it won't budge. Is it supposed to come out with all the front panel knobs/controls in place? Or, do the knobs come off and leave spindles/pots in place after removing any shaft nuts? A bit like 70's Pioneer HiFi when taking the front plate off. Either way, the knobs are stuck on and I can't even work out if these are push on with a spring clip or whether they are collet type. It looks like the top of the knob comes off to reveal a collet nut but that won't shift either. What a nightmare...

2nd Jul 2019, 9:00 pm	#4
wd40addict Octode Join Date: May 2009 Location: Stevenage, Herts. UK. Posts: 1,518	Re: Avo HF135 Access You definitely don't need to remove knobs. I'm afraid I can't check my unit at the moment to see if there's anything else that needs removing.

3rd Jul 2019, 7:36 am	#5
Stockden Heptode Join Date: Mar 2008 Location: Forest of Dean, Gloucestershire, UK. Posts: 648	Re: Avo HF135 Access It's a very long time since I played with one of these but I seem to recall that you also have to remove the 2 screws towards the middle of the back panel (i.e. the 2 that aren't round the edge). If I remember correctly these secure the back panel to the coil box and so stop the whole lot moving forwards. Hugh

3rd Jul 2019, 12:04 pm	#6
micheal Pentode Join Date: Mar 2007 Location: Croydon, London, UK. Posts: 111	Re: Avo HF135 Access As Stocken said remove two screws in centre of back. you do not need to remove knobs,but if at any time you do need to remove knobs pull top cap of knob with finger nail to reveal a collet nut be hind, i think it might be 7 or 8mm. Mike

5th Jul 2019, 10:29 pm	#7
twizzle Triode Join Date: Feb 2017 Location: Bradford, West Yorkshire, UK. Posts: 12	Re: Avo HF135 Access Thanks guys. I think the key to the puzzle is the x2 screws at the back that have been mentioned. That's not a combination I tried plus the front screws so I'm hopeful that'll sort it. I could feel the front panel held from moving in a way that was probably consistent with those rogue screws in place! As I said in my initial question, there's a combination to unlock the box somewhere and I didn't want to start shotgunning fixings if someone out there could provide the combination. I'll try it this weekend. Many thanks.