Pye CW17
 

Greetings,

After several years of mainly "lurking" on this forum I am now the proud owner of a Pye CW17-S. I also have an Aurora 405-line converter.

I admit that I was seduced by the esthetics of the Pye set. It is a design from Robin Day, not the TV personality but the designer. I have some experience restoring 1950s valve equipment -- mainly test gear such as signal generators and VTVMs. Plus have built homebrew ham gear with valve designs from that era.

On the plus side, the set I have purchased has raster (judging from the seller's photos) and is cosmetically in brilliant shape. On the minus side, because of its location, although I have purchased the set I cannot pick it up until Covid restrictions ease off. I am (perhaps optimistically) targeting early next year for the pickup, and the seller has agreed.

Meanwhile, I will track down the schematic and service information. Any advice would be most welcome. I have read several books about the 405-line system and servicing sets from this era, and did in fact coax a couple of these 1950s sets back to life ... as a teen-ager in the 1970s. One of them was a Pye. Otherwise I am a neophyte in these matters.

The photos below are from the seller.

Re: Pye CW17
 

I’m sure the TV guys and gals on here will give help and encouragement for you, noting the model number, do any of the TV engineers know if the S suffix is significant?
Regards, Alan

Re: Pye CW17
 

Yes, I was wondering about that. The chassis plate says it is a "17 - 21/S" but when looking for service sheets I cannot find a mention either of that designation, or the shorter "CW17 S" (from the back cover).

I've ordered some service docs and when I get them, things may become clearer.

Re: Pye CW17
 

I think the S stands for service area chassis, whereas F means a fringe area chassis (flywheel sync, extra gain, etc).

Re: Pye CW17
 

Here's the service info (click on graphic below).

I am slightly disappointed that this uses printed circuits, I like working on point to point! Still, we are talking about 1956-1957 when the PCBs were coming in.

Re: Pye CW17
 

Here is the type plate from the fringe chassis (F) version. I dismantled this set over 40 years ago.

Re: Pye CW17
 

The printed circuit version is a lot easier to work on than the wired version. It's also a lot easier to replace the components without getting a wiring fault due to a man made error.

The tube looks good from your picture. You will need to replace every paper 'tube' type capacitors throughout the chassis. They give an excellent picture.

You will need to obtain the exact manual/diagram for this chassis. Around this time PYE went mad producing loads of chassis differences with the same model number. Good luck with it. John.

Re: Pye CW17
 

That did occur to me! Hopefully a good starter set for this hobby.

Good. I was initially searching for slightly earlier sets, but was eventually attracted by the idea of a 17" CRT as the aim is not just to fix the set but to watch programmes.

I allegedly have the right one. The Type number (17-21/S) on the chassis matches the service sheet. See the two images below; I uploaded them earlier, but attached to separate posts.

Seems like the set came out in about 1956 but this is probably a later build, perhaps 1957.

Re: Pye CW17
 

The copper foil adhesion to the laminate isn’t as strong as in later years, so in order to avoid “lifted print” damage, I recommend you cut the component leads on the component side - near to the board itself - before you desolder the remnants on the copper side. Pye liked to twist the component wires into a small loop on the copper side of their PCBs! I find using desoldering braid helpful.

Re: Pye CW17
 

I agree with you there Daz, I was working on a Pye Dual Standard set yesterday. The print is very fragile and and those little twists are annoying to say least, care must be taken.

If that set is similar to my CTL58F then you're in for a real treat, absolutely great preformer.

Re: Pye CW17
 

The CTL58F was a great performer in very low signal areas with just a few millivolts. It was also called Continental I remember.

Re: Pye CW17
 

If it helps the Pye CW17 with various suffix versions has been publicised in the following;
E&E sheets 1272 & 1379
RER sheets TV122 & TV131
RTS books 1956-57 page 557 & 574, 1957-58 page s 511 & 536, 1958-59 page 552.

I also have the service manual ref RV30 March 1958, which covers models CW17S, CW17cs, CTM17S, CW21S and CTM21S (incorporating Twin printed panel chassis, type 17-21/S, with 'push & turn' horizontal hold control). There are also various loose sheets, 2 of which are labelled as 'RTL17 (wired chassis) to be used with CTM17/S service manual' and a sheet labelled 'circuit diagram B for CW17, CS17, CW17C, CS17C, CTM17T and 17TCDL (applicable to chassis with green paint dot close to name plate)'.

If it helps, I could do a scan for you but it will take a while, as there are a lot of oversize loose pages as well as quite a few in the manual.
Dave

Re: Pye CW17
 

It looks like I have that one (only). It starts on page 511 and ends on page 519, does that sound right? I bought it from a supplier online and the file name includes the characters "1957.RTV.TV".

What I have is quite good as far as it goes, but it would be great also to have scans of the more detailed material you mentioned. Absolutely no hurry, because I don't think I'll be able to collect the set before January or February.

Thank you so much!

Re: Pye CW17
 

The 1957-58 RTS book does go pages 511 to 519 but then page 519 carries on to page 527 with the models CTM17/S, LB17NF and RTL17. Page 528 begins the 21" range. Then page 536 to page 540 covers CW17, CW17F, CS17, CS17F, CW17C, CW17CF, CS17C, CS17CF, CTM17T, CTM17F and 17TCDL, where fig18 shows the circuit for the wired chassis. This later section also references to the earlier 1956-57 RTS book. It's all rather complex with the number of varients to this chassis and finding the exact info is somewhat of a challenge now that the oem service departments are no longer around.

If you want to PM me your email and let me know which info you would like scanned, I'll see what I can do for you.
Dave

Re: Pye CW17
 

There were 90 degree versions with either a magnetic MW43-80 or electrostatic AW43-80 tubes. Early versions used the 70 degree magnetic focus MW43-69.

The chassis could have been any combination of versions, hand wired printed circuit or half print and half wired either timebase or I.F. panel.

Add to this the full fringe variants and it can be confusing to sort out the correct manual but once sorted the chassis are quite straightforward.

LOPTs are reliable but it would be a good idea to warm up the overwind for a few days by passing a current through it as described in other threads. It is drenched in pitch!

A number of models had a small black button I think part of the contrast control that operated a switch in the cathode circuit of the video amplifier. This increased the definition to 3mc/s and it did work! John.

Re: Pye CW17
 

Hi Dave. It sounds like I might actually already have the correct pages for my chassis. Let's wait until I have the set and start working on it, and can confirm that it matches the service info that I have. I will PM my email address anyway.

Thanks again!