Cossor CDU130 Battery Portable Oscilloscope - UK Vintage Radio Repair and Restoration Discussion Forum

Chris55000 · 7th Sep 2021, 2:58 pm

Hi!

Bill Nichols "WME_Bill" has mentioned following an enquiry re circuits for the Cossor CDU130 Battery Oscilloscope, that he's never seen any circuits or bookwork for this, I'm pleased to announce that one of these CDU130s popped up on my eBay at a price that appealed, so I pulled the trigger, which gives me the opportunity to draw these!

The seller didn't mention any manual so I suspect there won't be one with it, but I will be starting my own home–written and drawn CDU130 book, which will be posted on here as I complete the sections, along with plenty of internal photos of the unit!

Chris Williams

PS!

There certainly has been more than one of these CDU130 oscilloscopes sold on eBay advertised complete with a handbook (one listed three years ago) but nobody's made any effort to scan or share this it seems!

Chris55000 · 9th Sep 2021, 1:24 pm

Hi!

The CDU130 (Serial No. 11221) has now arrived and on test, I got a whining–noise and a very dim blue line!

Reducing the T.B. speed revealed it was of the "P7" phosphor type with a blue fluorescence and a yellow afterglow, definitely not the very–short persistence
P11 I have come across on some 'scopes!

One for Bill – suggestions for a replacement conventional green CRT? – I suspect this P7 blue one will be quite badly low–emission by now, but I will be checking (and reporting on!) the condition of the internals as part of my drawing and Manual writing process!

Did any Member buy any of the CDU130s advertised with a handbook that came up for sale two/three years ago?

Neither Marc Christian from T.E. or the eBay Seller John Vincent who is selling many T & M manuals have the CDU130 book!

Chris Williams

PS!

It was the mains I tried it out on so lack of internal power–supply voltage shouldn't be an issue, unless, of course, the internal d.c./d.c. converter has gone grotty due to dried out electrolytics, etc!

WME_bill · 9th Sep 2021, 4:57 pm

CDU130.
Chris,
What is the Cathode Ray tube type number and maker, screen size and length please. I suspect it is a 4" diameter round tube, with pda. With that information, I will see if I can suggest alternative replacement tubes.
wme_bill.

Chris55000 · 9th Sep 2021, 5:01 pm

Afternoon Bill!

My ranting & raving friend'll be back soon so won't be able to investigate more tonight but I'll certainly be taking a closer look tomorrow, whilst he's at work, and then I'd add this information (and more!) to this post later tomorrow!

Chris Williams

PS!

It could certainly be p.d.a., but the trace brilliance I got was so poor it didn't look like it!

I have to admit, tho', you don't usually get "P7" unless requested specifically at the time of ordering brand–new – every 'scope handbook I have has always quoted a P7–type of CRT as a special option or to specific order – the last P7 CRT I saw was in a huge great Cossor 1035 about 43 years ago!

Chris55000 · 10th Sep 2021, 11:13 am

Hi!

Internal examination confirms, as Bill suggests, that the C.R.T. is of the p.d.a. type, there is an anode connector cap visible!

It's not too easy to count how many base–pins the CRT has because of the tangle of wiring and components around it's base, but it does appear to be the brown bakelite type of base rather than the all–glass B12F or B14G type!

There are three double–sided non–pth s.r.b.p. circuit boards, with red hand–written silk–screening on each side of them for component identification, PCB A is the vertical signal/deflection amplifier and trigger pick–off, PCB B is the trigger circuitry, Timebase and horizontal amplifier, plus some of the CRT adjustments, the e.h.t. transformer and rectifier(s) are buried inside somewhere, where I've not located them yet!

PCB C is the power supply converter, mounted in a passivated pressed aluminium box secured to the main chassis with two round–head screws and washers, this plugs in to two McMurdo type 10 way edge–connectors PL3 and PL4, marked both on the metalwork of the converter and silk–screened on PCB C!

It's certainly not impossible to draw out this Oscilloscope by any means, but there are a great many chassis–mounted components and other components suspended between ceramic strips, and it would be anybody's guess what Cossor's original component reference numbers for these would have been!

I haven't worked out how to remove the CRT yet!

Chris Williams

PS!

Mauritron haven't got a CDU130 book either!

Chris55000 · 10th Sep 2021, 12:40 pm

Hi!

The CRT has an anode cap, one single side pin connector and an 11 pin base of the all–glass type, so it'll probably be of a type that has the cathode internally connected to the heaters me thinks!

The anode cap lead is a length of red p.v.c. coloured wire with coloured number sleeves coded "15", this goes back to the power converter assembly, PL4/10, so the voltage isn't going to be all that high me thinks - there are two 33n 1000V moulded polyester type capacitors C513 and C515 here!

Chris Williams

Chris55000 · 10th Sep 2021, 1:30 pm

Hi!

As for the internal batteries, I found ten "Varta" RS3.5 D size (HP2) rechargeable NiCADs in the 'scope, two had gone white and furry on top but the other eight looked OK!

Anything about 4.0AH ought to do to replace them I think! The battery holders were varnished paxolin tubes and there was no damage done to the end contacts that I could see!

Chris Williams

I don't want to spend a lot of money on batteries, it would cost £100 (or more!) to replace them all and I'd much rather buy another CDU130 for that money!

Chris55000 · 29th Oct 2021, 4:50 pm

Hi!

I've now acquired a second CDU130, serial no. 14221, with a more conventional green CRT, and infuriatingly the seller told me an ex–workmate of his turfed out the book for it whilst the seller was away on holiday!

Chances are I've not yet identified all the earthy connections to PL3 and PL4 on the converter box yet, and the sketches I've made so far aren't making much sense – me thinks I'm going to have to list all the bits and de–populate one of the converters, and remove the transformer from the PCB to attempt to identify the windings individually, there's a considerable number of connections to this transformer!

I'm getting a "scope on" neon lit but so far I can't find much else on PL3 and PL4 voltage–wise anywhere!

Chris Williams

7th Sep 2021, 2:58 pm	#1
Chris55000 Nonode Join Date: Aug 2007 Location: Walsall Wood, Aldridge, Walsall, UK. Posts: 2,874	Cossor CDU130 Battery Portable Oscilloscope Hi! Bill Nichols "WME_Bill" has mentioned following an enquiry re circuits for the Cossor CDU130 Battery Oscilloscope, that he's never seen any circuits or bookwork for this, I'm pleased to announce that one of these CDU130s popped up on my eBay at a price that appealed, so I pulled the trigger, which gives me the opportunity to draw these! The seller didn't mention any manual so I suspect there won't be one with it, but I will be starting my own home–written and drawn CDU130 book, which will be posted on here as I complete the sections, along with plenty of internal photos of the unit! Chris Williams PS! There certainly has been more than one of these CDU130 oscilloscopes sold on eBay advertised complete with a handbook (one listed three years ago) but nobody's made any effort to scan or share this it seems! Attached Thumbnails __________________ It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed! Last edited by Chris55000; 7th Sep 2021 at 3:15 pm.

9th Sep 2021, 1:24 pm	#2
Chris55000 Nonode Join Date: Aug 2007 Location: Walsall Wood, Aldridge, Walsall, UK. Posts: 2,874	Re: Cossor CDU130 Battery Portable Oscilloscope Hi! The CDU130 (Serial No. 11221) has now arrived and on test, I got a whining–noise and a very dim blue line! Reducing the T.B. speed revealed it was of the "P7" phosphor type with a blue fluorescence and a yellow afterglow, definitely not the very–short persistence P11 I have come across on some 'scopes! One for Bill – suggestions for a replacement conventional green CRT? – I suspect this P7 blue one will be quite badly low–emission by now, but I will be checking (and reporting on!) the condition of the internals as part of my drawing and Manual writing process! Did any Member buy any of the CDU130s advertised with a handbook that came up for sale two/three years ago? Neither Marc Christian from T.E. or the eBay Seller John Vincent who is selling many T & M manuals have the CDU130 book! Chris Williams PS! It was the mains I tried it out on so lack of internal power–supply voltage shouldn't be an issue, unless, of course, the internal d.c./d.c. converter has gone grotty due to dried out electrolytics, etc! Attached Thumbnails __________________ It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed! Last edited by Chris55000; 9th Sep 2021 at 1:44 pm.

9th Sep 2021, 4:57 pm	#3
WME_bill Octode Join Date: Oct 2007 Location: Exeter, Devon, UK. Posts: 1,554	Re: Cossor CDU130 Battery Portable Oscilloscope CDU130. Chris, What is the Cathode Ray tube type number and maker, screen size and length please. I suspect it is a 4" diameter round tube, with pda. With that information, I will see if I can suggest alternative replacement tubes. wme_bill.

9th Sep 2021, 5:01 pm	#4
Chris55000 Nonode Join Date: Aug 2007 Location: Walsall Wood, Aldridge, Walsall, UK. Posts: 2,874	Re: Cossor CDU130 Battery Portable Oscilloscope Afternoon Bill! My ranting & raving friend'll be back soon so won't be able to investigate more tonight but I'll certainly be taking a closer look tomorrow, whilst he's at work, and then I'd add this information (and more!) to this post later tomorrow! Chris Williams PS! It could certainly be p.d.a., but the trace brilliance I got was so poor it didn't look like it! I have to admit, tho', you don't usually get "P7" unless requested specifically at the time of ordering brand–new – every 'scope handbook I have has always quoted a P7–type of CRT as a special option or to specific order – the last P7 CRT I saw was in a huge great Cossor 1035 about 43 years ago! __________________ It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed! Last edited by Chris55000; 9th Sep 2021 at 5:17 pm.

10th Sep 2021, 11:13 am	#5
Chris55000 Nonode Join Date: Aug 2007 Location: Walsall Wood, Aldridge, Walsall, UK. Posts: 2,874	Re: Cossor CDU130 Battery Portable Oscilloscope Hi! Internal examination confirms, as Bill suggests, that the C.R.T. is of the p.d.a. type, there is an anode connector cap visible! It's not too easy to count how many base–pins the CRT has because of the tangle of wiring and components around it's base, but it does appear to be the brown bakelite type of base rather than the all–glass B12F or B14G type! There are three double–sided non–pth s.r.b.p. circuit boards, with red hand–written silk–screening on each side of them for component identification, PCB A is the vertical signal/deflection amplifier and trigger pick–off, PCB B is the trigger circuitry, Timebase and horizontal amplifier, plus some of the CRT adjustments, the e.h.t. transformer and rectifier(s) are buried inside somewhere, where I've not located them yet! PCB C is the power supply converter, mounted in a passivated pressed aluminium box secured to the main chassis with two round–head screws and washers, this plugs in to two McMurdo type 10 way edge–connectors PL3 and PL4, marked both on the metalwork of the converter and silk–screened on PCB C! It's certainly not impossible to draw out this Oscilloscope by any means, but there are a great many chassis–mounted components and other components suspended between ceramic strips, and it would be anybody's guess what Cossor's original component reference numbers for these would have been! I haven't worked out how to remove the CRT yet! Chris Williams PS! Mauritron haven't got a CDU130 book either! Attached Thumbnails __________________ It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed! Last edited by Chris55000; 10th Sep 2021 at 11:20 am.

10th Sep 2021, 12:40 pm	#6
Chris55000 Nonode Join Date: Aug 2007 Location: Walsall Wood, Aldridge, Walsall, UK. Posts: 2,874	Re: Cossor CDU130 Battery Portable Oscilloscope Hi! The CRT has an anode cap, one single side pin connector and an 11 pin base of the all–glass type, so it'll probably be of a type that has the cathode internally connected to the heaters me thinks! The anode cap lead is a length of red p.v.c. coloured wire with coloured number sleeves coded "15", this goes back to the power converter assembly, PL4/10, so the voltage isn't going to be all that high me thinks - there are two 33n 1000V moulded polyester type capacitors C513 and C515 here! Chris Williams __________________ It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed! Last edited by Chris55000; 10th Sep 2021 at 12:47 pm.

10th Sep 2021, 1:30 pm	#7
Chris55000 Nonode Join Date: Aug 2007 Location: Walsall Wood, Aldridge, Walsall, UK. Posts: 2,874	Re: Cossor CDU130 Battery Portable Oscilloscope Hi! As for the internal batteries, I found ten "Varta" RS3.5 D size (HP2) rechargeable NiCADs in the 'scope, two had gone white and furry on top but the other eight looked OK! Anything about 4.0AH ought to do to replace them I think! The battery holders were varnished paxolin tubes and there was no damage done to the end contacts that I could see! Chris Williams I don't want to spend a lot of money on batteries, it would cost £100 (or more!) to replace them all and I'd much rather buy another CDU130 for that money! __________________ It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed! Last edited by Chris55000; 10th Sep 2021 at 1:59 pm.

29th Oct 2021, 4:50 pm	#8
Chris55000 Nonode Join Date: Aug 2007 Location: Walsall Wood, Aldridge, Walsall, UK. Posts: 2,874	Re: Cossor CDU130 Battery Portable Oscilloscope Hi! I've now acquired a second CDU130, serial no. 14221, with a more conventional green CRT, and infuriatingly the seller told me an ex–workmate of his turfed out the book for it whilst the seller was away on holiday! Chances are I've not yet identified all the earthy connections to PL3 and PL4 on the converter box yet, and the sketches I've made so far aren't making much sense – me thinks I'm going to have to list all the bits and de–populate one of the converters, and remove the transformer from the PCB to attempt to identify the windings individually, there's a considerable number of connections to this transformer! I'm getting a "scope on" neon lit but so far I can't find much else on PL3 and PL4 voltage–wise anywhere! Chris Williams __________________ It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed!