UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Solartron CD 1400 Oscilloscope Refurbishment

Chris55000 · 30th Jun 2020, 11:54 pm

Hi!

I've had a look through my extremely moth–eaten CD1400 book and RV304 is marked on my component layout diagram for PCB 3 (14009103) in the main unit, there's a value and type quoted for it plus setting–up instructions. RV304 is marked as a taller vertical rectangle just above the left–hand side of MR305 in the layout diagram.

R304 is referred to in my parts list as:–

"18K ¼W ±10%, Solartron Part No. 1723 41800 Erie Type 16 Carbon"

. . .and is marked on the component layout diagram as a very small hatched rectangle immediately below R312, along with Tag 15, but no pale orange lines representing the tracks are shown for either end of R304 or Tag 15, and it's not marked on either my Tech. Manual circuit, the Operating Booklet Circuit I have or the diagrams on Jon's Valve Page.

On my Operating Booklet Diagram, R309 and R315 are both marked as "330k" with additional 330k resistors R318 and R319 across R309 and R315 respectively, so Solartron may simply have fitted 150k in R309 and R315 positions – the modification adding R318 and R319 is mentioned in my parts list.

I would suspect that the left–hand end of R304 connects to the left–hand side of R312, etc., and the right–hand end of R304 leads off to Tag 15, am I correct?

The Board Assembly Removal Instructions for Board 3 make reference to 16 push–on connectors, or 17 in early models, but there's no written info on the tag wiring provided separately.

There is, by the way, hidden in the repair instructions, page 5 paragraph 32, a warning stating "components must not be unsoldered from the printed circuit", but if you have something like a Weller DSX80 or one of the "Duratool" heated vacuum desoldering–irons, you should be able to remove/desolder components if you use no more than 350–375°C or so.

Since you found R304 badly scorched/open circuit, obviously it's been passing current somewhere, but just exactly where?

My CD1400 looks like it could be fairly late production, so R304, Tag 15 and any wring to it could well have been deleted, but I'll have a check when I get time spare!

Chris Williams

30th Jun 2020, 11:54 pm	#15
Chris55000 Nonode Join Date: Aug 2007 Location: Walsall Wood, Aldridge, Walsall, UK. Posts: 2,868	Re: Solartron CD 1400 Oscilloscope Refurbishment Hi! I've had a look through my extremely moth–eaten CD1400 book and RV304 is marked on my component layout diagram for PCB 3 (14009103) in the main unit, there's a value and type quoted for it plus setting–up instructions. RV304 is marked as a taller vertical rectangle just above the left–hand side of MR305 in the layout diagram. R304 is referred to in my parts list as:– "18K ¼W ±10%, Solartron Part No. 1723 41800 Erie Type 16 Carbon" . . .and is marked on the component layout diagram as a very small hatched rectangle immediately below R312, along with Tag 15, but no pale orange lines representing the tracks are shown for either end of R304 or Tag 15, and it's not marked on either my Tech. Manual circuit, the Operating Booklet Circuit I have or the diagrams on Jon's Valve Page. On my Operating Booklet Diagram, R309 and R315 are both marked as "330k" with additional 330k resistors R318 and R319 across R309 and R315 respectively, so Solartron may simply have fitted 150k in R309 and R315 positions – the modification adding R318 and R319 is mentioned in my parts list. I would suspect that the left–hand end of R304 connects to the left–hand side of R312, etc., and the right–hand end of R304 leads off to Tag 15, am I correct? The Board Assembly Removal Instructions for Board 3 make reference to 16 push–on connectors, or 17 in early models, but there's no written info on the tag wiring provided separately. There is, by the way, hidden in the repair instructions, page 5 paragraph 32, a warning stating "components must not be unsoldered from the printed circuit", but if you have something like a Weller DSX80 or one of the "Duratool" heated vacuum desoldering–irons, you should be able to remove/desolder components if you use no more than 350–375°C or so. Since you found R304 badly scorched/open circuit, obviously it's been passing current somewhere, but just exactly where? My CD1400 looks like it could be fairly late production, so R304, Tag 15 and any wring to it could well have been deleted, but I'll have a check when I get time spare! 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; 1st Jul 2020 at 12:11 am.