Farnell Oscilloscope DTV60 - UK Vintage Radio Repair and Restoration Discussion Forum

bill knox · 10th Jul 2019, 12:58 pm

Hi

I have one of the above working quite well until last week when it went bang

taking the covers off the remnants of a 10uf electrolytic in the position C3018 fell out, also in a very sorry state was a resistor in position R3018 that just fell apart when touched

The problem is, I have a manual, but looking at it and compering the manual to the printed circuit board the two components do not agree with each other.

According to the scope R3018 and C3018 are across each other and according to the manual C3018 should be a .01uf ceramic capacitor.

Has anyone got one of these scopes that they could verify the value of R3018 and if they have a manual look at page 44 (Z - CRT) and see ifit is the same as my manual

Many thanks

Bill

bill knox · 22nd Jul 2019, 5:38 pm

Hi

Well, I have another Farnell DTV60 Scope in good working order, thinking that I could use the working one to check and fit new parts to the Non-working scope.

Unfortunately, it turns out that the main PC in my non- working scope is a version 3 and in the working scope the main board is a version 2 and they are as different as chalk and cheese and then, I find out that the manual is for a version 4 main board.

But at least I have a working scope.

Bill

Chris55000 · 22nd Jul 2019, 7:30 pm

Hi!

I think there are a number of "howlers" and inconsistencies between the parts lists and the circuit diagrams given in the manual that I could find!

C3018 is indeed called up in the parts list as "10μF 160V", but on the circuit it's been incorrectly marked up as "C3017", shown as being connected between the decoupled h.t.+ 145V line and it's –ve end returned to the emitters of Q3007 & Q3005.

There is indeed a 0μ01 disc ceramic between the collector of Q3007 & chassis, this should have been annotated "C3017" on the circuit diagram!

The h.t. decoupling–resistor is indeed called up as "R3018 100 Ω ¼W" on the parts list I could find, and annotated the same on the circuit–diagram, shown between Q3007 collector and the h.t. line.

Can you tell me what reference numbers are silkscreened on the top side of the PCBs please?

Chris Williams

bill knox · 23rd Jul 2019, 12:16 am

Hi Chris

Can you tell me what version of the manual that you have, if you look at the page with the circuit of the main board and look at the bottom of the page, the last 2 digits are the version of the main board, either 02,03, or 04.

The component positions are, R3018 Burnt to crisp and C3018 10uf I cannot read the voltage as all that is left is the case and a bit of shrivelled plastic, according to the PCB they are across each other, I have bought some 10uf 250v WKG but I could not work the collector resistor. is the resistor and capacitor what they say on the board or are they in fact some other circuit references.

Regards

Bill

Regards

Bill

Chris55000 · 23rd Jul 2019, 1:16 am

Hi!

All the documentation I can find on the DTV60 refers to a main board type "5206–01–03A" in which both C3017 and C3018 are shown as positions for electrolytics, using the "Hong Kong" type symbol (two "plate" lines with angled lines joining them together), and a circle to denote the +ve pole.

The parts list from the same manual quotes C3017 as "0μ01 ceramic" whilst the circuit diagram quotes C3017 on p44 as a 1μ 160V electrolytic! C3018 is on the diagram as a "0.01" non–polarised capacitor and "10μ 160V electrolytic" on the parts list!

I almost certainly think the remains of the 10μ electrolytic you removed from C3018 position would have been a 160V type!

R3018 is consistently given as "100 Ω" on both the parts list and diagram – I think you can rely on this – it's a reasonable value for a h.t. feed/decoupler!

I dread to think how many other "howlers" there are like this in this manual, with the usual nonsense added "details subject to alteration without notice" – in other words, "don't expect us to make any correction of errors!"

Worse, I've just noticed the parts list does in fact quote C3018 twice, once as "0μ01 disc ceramic" and again as "10μ 160 V electrolytic" but I haven't found any other references to C3018 except adjacent to R3018 in either the layout or circuit diagrams!

Regrettably I don't have an actual DTV60 to refer to I'm afraid!

Chris Williams

bill knox · 23rd Jul 2019, 10:01 am

Hi Chris

That is some very interesting information, at least now I can fit the 100 ohms resistor and the capacitor.

I checked the HT voltage and it is actually 143.5V so that looks OK, I cannot see any other reason that the cap blew itself to pieces, so by my reasoning the cap blew up taking the 100ohms resistor out, I hope that is all that is wrong.

Would there be any chance of a copy of the parts layout and the circuit diagram for the main board, where did you get your copy of the manual from, up until last week I was under the impression that I had the correct manual, nowhere in the beginning of the manual does it say what version it is, it's only when something like this happens and then the penny drops.

If you would like a copy of my manual I will get one together for you .

Regards

Bill

Chris55000 · 24th Jul 2019, 9:18 am

Hi!

My copy came from ElektroTanya originally! Two parts of it are attached here to this note!

If yours differs, could I have a copy please?

Chris Williams

PS!

I was reading this on a small phone screen so I may not have spotted all the howlers, but in the parts list, all the "Metal Graze" Resistors should say "Metal Glaze" of course, many Far Eastern people make this mistake translating their mother tongue into English!

If you need to replace any of these, use Vishay VR37 Metal Glaze High Voltage types or equivalent for replacement purposes!

bill knox · 24th Jul 2019, 10:55 pm

Hi Chris

Thank you for the manual, I have had a quick look but I would say that it is the same as mine, but just to make sure I am attaching my manual to this note.

If for whatever they do NOT attach let me know and I will do something else.

You mention VR37 metal glaze resistors, where are they obtainable from, Farnell - RS online

??

Regards

Bill

Chris55000 · 25th Jul 2019, 8:59 am

Hi!

Your copy obviously came from the same source as mine!

A few values of VR37 Metal Glaze Resistors rated @ 3500V for Oscilloscope use are stocked at RS & Farnell, but a much better range can be obtained from Mouser UK, altho' I believe Mouser may have a minimum order charge!

Some of the more esoteric values in E24 can be obtained from eBay, so there shouldn't be too much bother getting what you need for the E.H.T. divider chains or multiplier circuits in most oscilloscopes!

Chris Williams

10th Jul 2019, 12:58 pm	#1
bill knox Hexode Join Date: Mar 2011 Location: Wilstead, Bedfordshire, UK. Posts: 367	Farnell Oscilloscope DTV60 Hi I have one of the above working quite well until last week when it went bang taking the covers off the remnants of a 10uf electrolytic in the position C3018 fell out, also in a very sorry state was a resistor in position R3018 that just fell apart when touched The problem is, I have a manual, but looking at it and compering the manual to the printed circuit board the two components do not agree with each other. According to the scope R3018 and C3018 are across each other and according to the manual C3018 should be a .01uf ceramic capacitor. Has anyone got one of these scopes that they could verify the value of R3018 and if they have a manual look at page 44 (Z - CRT) and see ifit is the same as my manual Many thanks Bill

22nd Jul 2019, 5:38 pm	#2
bill knox Hexode Join Date: Mar 2011 Location: Wilstead, Bedfordshire, UK. Posts: 367	Re: Farnell Oscilloscope DTV60 Hi Well, I have another Farnell DTV60 Scope in good working order, thinking that I could use the working one to check and fit new parts to the Non-working scope. Unfortunately, it turns out that the main PC in my non- working scope is a version 3 and in the working scope the main board is a version 2 and they are as different as chalk and cheese and then, I find out that the manual is for a version 4 main board. But at least I have a working scope. Bill

22nd Jul 2019, 7:30 pm	#3
Chris55000 Nonode Join Date: Aug 2007 Location: Walsall Wood, Aldridge, Walsall, UK. Posts: 2,868	Re: Farnell Oscilloscope DTV60 Hi! I think there are a number of "howlers" and inconsistencies between the parts lists and the circuit diagrams given in the manual that I could find! C3018 is indeed called up in the parts list as "10μF 160V", but on the circuit it's been incorrectly marked up as "C3017", shown as being connected between the decoupled h.t.+ 145V line and it's –ve end returned to the emitters of Q3007 & Q3005. There is indeed a 0μ01 disc ceramic between the collector of Q3007 & chassis, this should have been annotated "C3017" on the circuit diagram! The h.t. decoupling–resistor is indeed called up as "R3018 100 Ω ¼W" on the parts list I could find, and annotated the same on the circuit–diagram, shown between Q3007 collector and the h.t. line. Can you tell me what reference numbers are silkscreened on the top side of the PCBs please? 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; 22nd Jul 2019 at 7:42 pm.

23rd Jul 2019, 12:16 am	#4
bill knox Hexode Join Date: Mar 2011 Location: Wilstead, Bedfordshire, UK. Posts: 367	Re: Farnell Oscilloscope DTV60 Hi Chris Can you tell me what version of the manual that you have, if you look at the page with the circuit of the main board and look at the bottom of the page, the last 2 digits are the version of the main board, either 02,03, or 04. The component positions are, R3018 Burnt to crisp and C3018 10uf I cannot read the voltage as all that is left is the case and a bit of shrivelled plastic, according to the PCB they are across each other, I have bought some 10uf 250v WKG but I could not work the collector resistor. is the resistor and capacitor what they say on the board or are they in fact some other circuit references. Regards Bill Regards Bill

23rd Jul 2019, 1:16 am	#5
Chris55000 Nonode Join Date: Aug 2007 Location: Walsall Wood, Aldridge, Walsall, UK. Posts: 2,868	Re: Farnell Oscilloscope DTV60 Hi! All the documentation I can find on the DTV60 refers to a main board type "5206–01–03A" in which both C3017 and C3018 are shown as positions for electrolytics, using the "Hong Kong" type symbol (two "plate" lines with angled lines joining them together), and a circle to denote the +ve pole. The parts list from the same manual quotes C3017 as "0μ01 ceramic" whilst the circuit diagram quotes C3017 on p44 as a 1μ 160V electrolytic! C3018 is on the diagram as a "0.01" non–polarised capacitor and "10μ 160V electrolytic" on the parts list! I almost certainly think the remains of the 10μ electrolytic you removed from C3018 position would have been a 160V type! R3018 is consistently given as "100 Ω" on both the parts list and diagram – I think you can rely on this – it's a reasonable value for a h.t. feed/decoupler! I dread to think how many other "howlers" there are like this in this manual, with the usual nonsense added "details subject to alteration without notice" – in other words, "don't expect us to make any correction of errors!" Worse, I've just noticed the parts list does in fact quote C3018 twice, once as "0μ01 disc ceramic" and again as "10μ 160 V electrolytic" but I haven't found any other references to C3018 except adjacent to R3018 in either the layout or circuit diagrams! Regrettably I don't have an actual DTV60 to refer to I'm afraid! 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; 23rd Jul 2019 at 1:28 am.

23rd Jul 2019, 10:01 am	#6
bill knox Hexode Join Date: Mar 2011 Location: Wilstead, Bedfordshire, UK. Posts: 367	Re: Farnell Oscilloscope DTV60 Hi Chris That is some very interesting information, at least now I can fit the 100 ohms resistor and the capacitor. I checked the HT voltage and it is actually 143.5V so that looks OK, I cannot see any other reason that the cap blew itself to pieces, so by my reasoning the cap blew up taking the 100ohms resistor out, I hope that is all that is wrong. Would there be any chance of a copy of the parts layout and the circuit diagram for the main board, where did you get your copy of the manual from, up until last week I was under the impression that I had the correct manual, nowhere in the beginning of the manual does it say what version it is, it's only when something like this happens and then the penny drops. If you would like a copy of my manual I will get one together for you . Regards Bill

25th Jul 2019, 8:59 am	#9
Chris55000 Nonode Join Date: Aug 2007 Location: Walsall Wood, Aldridge, Walsall, UK. Posts: 2,868	Re: Farnell Oscilloscope DTV60 Hi! Your copy obviously came from the same source as mine! A few values of VR37 Metal Glaze Resistors rated @ 3500V for Oscilloscope use are stocked at RS & Farnell, but a much better range can be obtained from Mouser UK, altho' I believe Mouser may have a minimum order charge! Some of the more esoteric values in E24 can be obtained from eBay, so there shouldn't be too much bother getting what you need for the E.H.T. divider chains or multiplier circuits in most oscilloscopes! Chris Williams __________________ It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed!