Gould 4074 Dented rear Panel! - UK Vintage Radio Repair and Restoration Discussion Forum

Chris55000 · 31st Oct 2023, 3:34 pm

Does anyone know how I can straighten this dented Back Panel of a Gould 4074 Oscilloscope please?

(I put this one in our spare room three years ago because there was a burning smell coming from it, and forgot about it – it was only when I got out the big 545A and a 465 to take to Jez in Northumberland it cane to light, hidden at the back of the room!)

This is obviously careless courier damage from being dropped on its back end me thinks!

Having got it out, I'm trying to put all the mechanicals to rights mainly – it powers up OK and passes self–test/self–calibration OK – all the alphanumerics are undistorted, sharply focused and evenly spaced on the screen, so the CRT has survived OK!

This is why I have put in several 4074 related requests for parts, by the way!

Chris Williams

Techman · 31st Oct 2023, 8:14 pm

I can't see exactly what's happened in your pictures, but I've had a few things like this and I find that a couple of blocks of wood and a big hammer soon sorts it out - preferably done outside on a hard surface when it's not raining!

Chris55000 · 31st Oct 2023, 9:04 pm

It would normally be dead easy if it wasn't for the fact that Gould welded the fixing posts for the rear rubber blocks to the panel, meaning that its difficult to get a purchase on the face with a hammer, unless you make a special jig that the posts can drop into, and I don't have a Workmate that would help with this!

Chris Williams

peterpixel · 1st Nov 2023, 12:22 am

Hi Chris,if the fixing posts are the black projections shown in picture #1 then I would invert the panel and insert the posts loosely into a heavy bench vice and then apply the required percussion treatment. If the vice jaws are not substantial enough then the careful application of pieces of right angle steel to enlarge the bulk of the jaws should help. I once repaired a Sony BVU 110 chassis that had been jumped on during the street riots in the 1980s using the same method. That was aluminium but the principal is the same, it just needs a bigger hammer. Best regards, Peter.

Radio Wrangler · 1st Nov 2023, 5:48 am

Be careful of too much percussive therapy, it stretches the metal and you wind up making more surface area than the periphery used to contain, making a domed panel or irreducible bumps. Going at it with a 'shrinking hammer' and dolly would wreck paintwork and labelling. What I've done in the past is to make hardwood tooling for both sides and pressed things back to shape with a big vice. Leaving it a long time to creep to shape.

I bought a really nice Sony FM tuner from the offered section on here. It suffered a bad drop in the hands of some couriers, shoving the tuning knob in about 20mm by bending internal framing. It took panel beating work (and firing up the TIG to fix cracks), but I got it there. There had been no cosmetic damage to the case or the knob. A bit of stiffening was added to stop the framing flexing when push buttons were operated.

Re-flattening an exposed panel is never going to be perfect. Making tooling is the easy option!

David

Station X · 1st Nov 2023, 10:58 am

Faced with that I'd put suitable packing under the outside and apply pressure from an hydraulic press to the inside. This gives very precise control of the process and it's easy to see whether things are going correctly.

If you'd care to post it to me (well packed of course!) I'll give it a try, but obviously I can't guarantee success.

Chris55000 · 1st Nov 2023, 12:07 pm

Perfect – I'll take up Graham's offer and see how it goes!

PM sent to "Station X" Graham!

Chris Williams

31st Oct 2023, 8:14 pm	#2
Techman Dekatron Join Date: Nov 2009 Location: Lincolnshire, UK. Posts: 5,000	Re: Gould 4074 Dented rear Panel! I can't see exactly what's happened in your pictures, but I've had a few things like this and I find that a couple of blocks of wood and a big hammer soon sorts it out - preferably done outside on a hard surface when it's not raining!

31st Oct 2023, 9:04 pm	#3
Chris55000 Nonode Join Date: Aug 2007 Location: Walsall Wood, Aldridge, Walsall, UK. Posts: 2,874	Re: Gould 4074 Dented rear Panel! It would normally be dead easy if it wasn't for the fact that Gould welded the fixing posts for the rear rubber blocks to the panel, meaning that its difficult to get a purchase on the face with a hammer, unless you make a special jig that the posts can drop into, and I don't have a Workmate that would help with this! Chris Williams __________________ It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed!

1st Nov 2023, 12:22 am	#4
peterpixel Pentode Join Date: Jul 2013 Location: Wilmslow, Cheshire, UK. Posts: 210	Re: Gould 4074 Dented rear Panel! Hi Chris,if the fixing posts are the black projections shown in picture #1 then I would invert the panel and insert the posts loosely into a heavy bench vice and then apply the required percussion treatment. If the vice jaws are not substantial enough then the careful application of pieces of right angle steel to enlarge the bulk of the jaws should help. I once repaired a Sony BVU 110 chassis that had been jumped on during the street riots in the 1980s using the same method. That was aluminium but the principal is the same, it just needs a bigger hammer. Best regards, Peter.

1st Nov 2023, 5:48 am	#5
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,915	Re: Gould 4074 Dented rear Panel! Be careful of too much percussive therapy, it stretches the metal and you wind up making more surface area than the periphery used to contain, making a domed panel or irreducible bumps. Going at it with a 'shrinking hammer' and dolly would wreck paintwork and labelling. What I've done in the past is to make hardwood tooling for both sides and pressed things back to shape with a big vice. Leaving it a long time to creep to shape. I bought a really nice Sony FM tuner from the offered section on here. It suffered a bad drop in the hands of some couriers, shoving the tuning knob in about 20mm by bending internal framing. It took panel beating work (and firing up the TIG to fix cracks), but I got it there. There had been no cosmetic damage to the case or the knob. A bit of stiffening was added to stop the framing flexing when push buttons were operated. Re-flattening an exposed panel is never going to be perfect. Making tooling is the easy option! David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

1st Nov 2023, 10:58 am	#6
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Gould 4074 Dented rear Panel! Faced with that I'd put suitable packing under the outside and apply pressure from an hydraulic press to the inside. This gives very precise control of the process and it's easy to see whether things are going correctly. If you'd care to post it to me (well packed of course!) I'll give it a try, but obviously I can't guarantee success. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

31st Oct 2023, 3:34 pm	#1
Chris55000 Nonode Join Date: Aug 2007 Location: Walsall Wood, Aldridge, Walsall, UK. Posts: 2,874	Gould 4074 Dented rear Panel! Does anyone know how I can straighten this dented Back Panel of a Gould 4074 Oscilloscope please? (I put this one in our spare room three years ago because there was a burning smell coming from it, and forgot about it – it was only when I got out the big 545A and a 465 to take to Jez in Northumberland it cane to light, hidden at the back of the room!) This is obviously careless courier damage from being dropped on its back end me thinks! Having got it out, I'm trying to put all the mechanicals to rights mainly – it powers up OK and passes self–test/self–calibration OK – all the alphanumerics are undistorted, sharply focused and evenly spaced on the screen, so the CRT has survived OK! This is why I have put in several 4074 related requests for parts, by the way! Chris Williams Attached Thumbnails __________________ It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed!

1st Nov 2023, 12:07 pm	#7
Chris55000 Nonode Join Date: Aug 2007 Location: Walsall Wood, Aldridge, Walsall, UK. Posts: 2,874	Re: Gould 4074 Dented rear Panel! Perfect – I'll take up Graham's offer and see how it goes! PM sent to "Station X" Graham! Chris Williams __________________ It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed!