The Hertfordshire Rediffusion MK1s

To be honest Tas, scraping the cabinet and then applying some Danish Oil would make them look superb from what I can see.

Hi Tas,

Rediffusion-tastic

Looks like you're going to have a Rediffusion March/April sorting that lot out. There's been a glut of these sets turning up recently which is great. It will be interesting to see how they fair on soak, watch the tripler Gary's CU2213 let go after a few hours. Nice sets to work on, well thought out too and we have the resident Rediffusion guru here Malc. He may even be able to sort you out with a TMB board. Service data as you are aware is in the library

My CU2213 had some bad scratches and water stains, it was easy to sort and as you can see from the main site photos, looks great now. Mikes right a good sanding and danish oil will work wonders.

Chris

Nice lot of sets you have there. Straightforward restorations. I have plenty of spares and help here, Malc.

Thanks for your comments guys. I get the feeling that these sets may have been stored in less than favourable conditions. The convergence controls in particular a scratchy and rusty too. That's gonna need sorting too.

One set is earmarked for Aiden Lunn who expressed an interest way back when I was bidding.

Ta for now!

That failure of finish is definitely indicative of damp conditions, Tas.

Good evening!

A little bit of tinkering yesterday brought some rather better results.

First of all, the CU2214. This had appalling convergence and very bad field linearity amongst its main faults. There was no chance of setting up the convergence as two of the pots were open circuit. They were RV712 and RV710 Red/Green field amplitude and tilt. with one at one end there was a marked improvement to the lin but the convergence was still miles out. Several of the other pots were scratchy too but with none in my spares stash I robbed the panel out of the wrecked CU2213 which looked in surprisingly good nick. I wonder if it had been replaced later in it's life? This now enabled the convergence to be set up and the linearity was now almost correct. When I say almost, there is some foldover at the bottom of the raster. Any ideas on this?

The chroma was a little hesitant to arrive at switch on although could be made to appear by disabling the colour killer. A touch to the ACC preset sorted out reliable colour operation.

The width was a little lacking so I treated the set to a brand new PL509 and PY500 pair. That cured the width problem and speeded up the warm up time too.

So faults to still work through are the small amount of bottom foldover, rather weak contrast, the black level seems to float up and down with picture content and of course there the very bad cabinet to attend to.

As for the CU2211, I haven't really done too much to that other than a very rough set up. Again dodgy convergence pots, the same as above precluded decent convergence and again the lin is not right. The picture in general has a bit more "punch"on this set though. I'll certainly need some of those orange convergence pots - 20ohms centre tap I think. I don't want to do too much to this one though as it may well be passed onto Aidan.

On both sets there is not much range on the brightness controls. Is that normal?

As to the "scrapper" I'm ha;f tempted to borrow a timebase panel from one of the above two just to see what happens. It also needs a new PY500 which has gone down to air - I have a few!

Anyway, here's some pics of the progress so far.

Tas

Hi Tas, plenty of nos convergence pots for these here, Malc.

Great results. I'm not at all familiar with this chassis. The only example I remember was a cable version a relative had. It was returned when the service closed in the early '80s.
Brian

Hi Tas, plenty of nos convergence pots for these here, Malc.

That's great Malc. Can I purchase some?

Tas

Great results.

There's still a way to go yet mate

I'm not at all familiar with this chassis.

Me neither other than one that my aunty and uncle rented from Rediffusion in Cardiff which replaced a Rediffusion badged Luxor Hybrid set.

Tas

Hi Tas, let me know what values you need and a pic of the types, Malc.

Hi Malc.

I need four of the 20ohm ones (with the orange spindle in the photograph) and one of the 200ohm ones (with the blue spindle in the photo). Drop me a message and we'll do business

Here's the photos.

Hi Tas, i have sorted out 4 x 15 ohm and 1 x 200 ohm nos pots. I used the 15 ohm in place of the 20 ohm pots in my Mk1 and they worked fine. PM me your address and i will pop them in the post for you on Monday, Malc.

Tas, also check the condition of the shift pots on the eht tower sub pcb, Malc.

Checked Malc. The line shifts pots are fine but the frame shift ones are a bit "iffy"!

Tas

Hi Tas, convergence pots are on their way. I have included a couple of nos 1k vert shift pots, Malc.

Hello again and big thanks to Malc for the convergence pots.

I had a little spare time today so set about replacing some of the duff pots in the 2211. The improvement was dramatic as the photos show. There are a few niggles but I'll let Aidan (assuming he still wants the set!) finish things off.

I couldn't resist having a look at whether the CU2213, which if you remember was the one that I reckon had been thrown together using the worst of some other sets, would produce any worthwhile results. In its "as found" condition, the timebase panel was missing and plugs were out on the decoder board. The PY500 was also down to air. I nicked the timebase board out of my CU2214, stuck a second-hand PY in and plugged the decoder back in. If you remember, I stole the convergence board from the 2213 to put into my 2214 as it was in much better nick so I first had to replace a couple of the dodgy pots on the convergence panel that now lived in the 2213. With this done and the mains filter cap snipped, it was time to apply power.

With more than a little surprise, I soon had a raster and after a bit of tuning, signals and sound. The convergence was miles out, the scan coils "on the p1ss", grey scale laughable and no colour but it was a start. I'd already tested the CRT so I knew despite it being a regun, it was very low. With nothing to lose I thought I'd give it a bop with my machine but I reckon someone had been there before me. The green was shot and would not boost, blue not much better although red was pretty good. I had a very quick go at lining it up and it converged ok - from what I could see! Overriding the colour killer produced colour with severe Hanover blinds (bistable trouble?) Anyhow, that's as far as I'm gonna go with that one (I think - although I maybe tempted to get the decoder working!)

I'll move back on to the "keeper" when I have more time and will pick your brains again.

Regards,

Tas

Glad to see it's being awoken by someone more adept at vintage colour TV than myself, and yes I do still want it Tas

The plan at my end is to restore all my valve B&W TVs, then go on to my few solid-state b&w sets, then move onto colour. This Rediffusion might provide a good "training ground" for colour before I do both my Thorn 8500s. That way i feel I can make progress into learning the hardware of more complex TV sets, by starting off with the easiest (B&W valve TVs).

Hi Aidan.

Glad to hear you're still interested. I just hope I have left enough stuff for you to do. We'll have to work out how to get the set to you.

Anyway, onto the basket case CU2213. As I knew would happen, I couldn't resist trying to sort out the decoder. If you remember, with the colour killer overridden, there was some colour albeit wrong and with severe blinds. There wasn't much scientific fault finding other than knowing from the symptoms that it was in the area of the ident/bistable and sure enough a little electrolytic capacitor (C221 12uF) decided to own up by giving off a puff of electrolyte! With this replaced, we now had colour. I then went through the process of setting everything up. This set really had been thrown together using panels from other Mk1's. In spite of the lousy CRT the set now gives quite a pleasing picture. I paid £30 for the three of them so if anyone wants this CU2213, a tenner secures it. The cabinet will require a lot of work and it really could do with a better CRT and of course it'll need a timebase panel as it has the one borrowed from my CU2214. Anyway, here's the pictures of today's work.

Tas