Scopex 4D10 and 4D25 oscilloscopes

[Brian of Romsey]

Hi, I'm a newbie here, but I have been reading some old, closed, threads about the Scopex oscilloscopes.

I have recently been given a 4D10 and a 4D25. They are both quite dirty, but they both 'light up'. The 4D10 is working OK, as far as I've tested. It displays a 1 KHz calibration signal OK, on both channels. The 4D25's vertical section is working OK, but the horizontal deflection has some sort of fault, the beam(s) never deflect left of centre. They deflect right OK, and the right hand end of the trace moves correctly in response to the horizontal position. The left hand end of the trace is a bright dot.

I am trying to decide if I should sell, give away, or repair. So I'm looking for manuals (isn't everyone?). Note that these are original models, not the later A or B variants. Note that I have managed to find the manual for the 4D10A but as other posters have noted it is quite different to the 4D10.

I also received a proper Scopex padded blue fabric bag that I presume is some sort of travel protection for use on the road by travelling engineers. It does need a a bit of a wash though.

Thanks in advance, Brian.

[karesz*]

Hi Brian,

do you know these site? http://www.collection.archivist.info...hstr=Scopex+IS

Karl

[WME_bill]

The mention of the Web site collection The Archivist prompts me to ask: Has anyone managed to get in touch with this chap or download any of his manuals. I have completely failed to find where or how to go further from his web site. So I have given up, and got what I wanted elsewhere. But not the 4D25.
I have the manuals for the 4D10A and the 4S6. I have a note that the 4D10 uses a 733 Y amp and TTL for the trigger/TB. While the 4D10A uses discrete Y and discrete TB. So not much help I'm afraid.
wme_bill

[Brian of Romsey]

Hi karesz, yes I have been all over archivist.info. But, like WME bill, I can't actually find any way to download anything from the site.

My 4D10, serial number 5908, is very strictly transistors, diodes, Rs, Cs, and a couple of inductors. No DIP components or 8 pin TO5s. Pretty much everything on a single phenolic paper PCB, with a roughly 10 cm square HV PCB on the back panel with six 16 μF 500 V caps.

Bill, in Aug 2011 you implied that you have some sort of documentation for the 4D10 (as distinct from the 4D10A). Is that still the case? If so may I have a copy please?

Thanks, Brian.

[Brian of Romsey]

I have studied the schematic in the 4D10A document and what I can't work out is where the chop/alt stuff is and hence how that part works.

[Herald1360]

Buried in the Archivist front page:

To contact me dave dot thearchivist at gmail dot com

He also talks about donations and contact him if you want something scanning.

[WME_bill]

Scopex 4D10 and 4D10A.
I have found manuals for both versions. They seem very similar. I have checked up, and my remarks of 24 July about use of 733 IC etc relate to the later model 14D10, not the 4D10.
I will scan the 4D10 for Brian at Romsey.
His question about where is the beam switching on 4D10A:
On the Vertical amplifiers & Beam switch circuit. The diode networks D53A to D56A for Channel A and D53B to D56B for Channel B are switched on by the voltage pulse through R71A and R71B, driven from the multivibrator pair TR302-303, and with TR301 driven from the timebase for the alternate action.
The action is described in the manual. The zener diodes D51-52 are not part of the switching as such, but form an ingenious level changing arrangement.
wme_bill

[WME_bill]

Scopex 4D10.
for Brian at Romsey. Herewith the manual for the Scopex dual trace 10Mhz oscilloscope, original 4D10 version.
I have had to omit a couple of pages of no importance, purely presentational, so as to keep it within the posting limits of this Forum.
Do let us know what the problems are and how you solved them.

Talking about The Archivist as a source of manuals, have you come upon the other great eccentric source (and I am sure he will not mind the description) Diverse Devices at Southampton. He had provided me with copies of unusual manuals of which he is often the only source, readily and at at a very reasonable price.
wme_bill. m0wpn

[karesz*]

I have created an Scopex 4D25.pdf SM from "The Archivist" jpg docs, but its more as 12MB. Please mail me if somebody need it...
Regards, Karl

[MotorBikeLes]

It is a long time since I played in a 4D10, but TAKE CARE if you disturb the Y amp input transistors. VERY static sensitive.
From memory, there are a number of high value resistors in parallel with 4.7UFd capacitors in the HV section. If one goes O/C, its associated capacitor can suffer and I think various other semicons can get killed. Check them all and replace if in doubt. From memory, I think they were 2M2ohms, but may be wrong.
Les.

[karesz*]

Brian-and everybody,
an Scopex 4D25.pdf is downloadable from here.

Regards, Karl

[Brian of Romsey]

Hi,

WME_bill, thanks a lot for the scan of the 4D10 manual. karesz, thanks a lot for the the pointer to the scan of the 4D25 manual. Brilliant!

Brian.