I am kicking myself, and regretting what I did during a big clear out two or three years ago. I had two Pye 169 chassis sets, a 24 and a 20 inch. (Had horrible half-turn screws that never seemed to hold the backs on). Both were in poor physical condition and with worn out tubes, but they worked. I took them down the tip.
To understand the black art of electronics is to understand witchcraft. Andrew.
Thanks Hamid.
I've asked the question. Looks like a good site to have a look around!
Scoured the site, and emailed them, but never had a reply 🙁
I am kicking myself, and regretting what I did during a big clear out two or three years ago.
I had two Pye 169 chassis sets, a 24 and a 20 inch. (Had horrible half-turn screws that never seemed to hold the backs on).
Both were in poor physical condition and with worn out tubes, but they worked.
I took them down the tip.
Don't beat yourself up about it. One will turn up.
Thanks for the tip on the 210 loptx Malc, I may just put that up in a min.
Thanks, it's all too easy to look back at things that were chucked out and then regret it. 
To understand the black art of electronics is to understand witchcraft. Andrew.
Well, after a bit of a wait.... a very kind member (who wishes to remain anonymous) has found and sent me a very nice shiny Lopt, It's a Konig ZTR371 , which is apparently a replacement for the Philips 300 series single-standard sets. It has a stick rec molded into the overwind, so I can do away with the EHT rec.
I've got the circuit diagram for the 169, and the relevant bit of the circuit for the 300 from LLJ's article (no 214) , but I can't marry up the pins on the ZTR371 and the 300 diagram. Now I have the correct number of pins (minus 2, for the EHT Rec) but the value of the capacitors hanging off the pins vary a bit, as does the 1K resistor, presumably across the line lin control to give it a bit of damping (it's 1.5K), and don't appear to make much correlation to the pin labelling A-N (No I )) I also appear to have a pin, with a 150pF cap on it going to another pin with no winding connected to it. That maybe pin H, C5005. If that's the case, I'm not sure what the other cap is (which may be between pins J and G (22pF on the TX, 20pF on the diagram), but they aren't in alphabetical order.
Does anyone have a 300 to hand they can get a shot of the LOPT and/or print side of the timebase panel so I attempt to make some sense of it all? Or a 300 timebase panel they can lend me to look at?
I'd hate to cook a new lopt....
A picture tells a thousand words ...
You're not telling us you've *finally* got a LOPT, are you?!
Not quite. But it looks graftable. Read the end of page 1
Rough sketches of the connections to the line output transformer that was used in the Philips 300 series single standard TVs. In dual standard sets the tags D and F are connected to the 405/625 switch.
The Pye line output circuit will not differ all that much from the Philips.
Tag H connects to the C5005 which is the width control feedback capacitor. In the Pye 169 it might be located on the PCB.
Till Eulenspiegel.
Thanks Till. That should be enough to make a start.
I'll keep the thread updated.
Further examination of the service information for the 169 chassis reveals that line timbase stabilising feedback capacitor is C71 and it fitted on the PCB. If that is the case then the feedback capacitor on the Konig transformer (if fitted) should be removed. It's likely the same type of line output transformer was also employed in the dual standard 368 chassis. After 1967 many more Philips sourced components were being used in Pye group sets.
I'd reckon your Konig 300 series transformer will work in the 169.
Till Eulenspiegel.
Hi, Doz, RR here. Have you got a big soldering gun like the old weller 140 watt type? If so will that melt the glue holding that transformer together? better try it outside as it'll make dreadful fumes if it does work. Or is the glue inside between the former and the core where you can't get at it? RR.
Hi, Doz, RR here. Have you got a big soldering gun like the old weller 140 watt type? If so will that melt the glue holding that transformer together? better try it outside as it'll make dreadful fumes if it does work. Or is the glue inside between the former and the core where you can't get at it? RR.
To what end?
The glue on the original transformer is like some form of cement. Nothing seems to soften it.
Right, I've made a start. The big issue seems to be the Pye's lack of S-correction cap, the coils are fed in series with the line lin inductor.
I've removed the line line inductor, and it's damping resistor, and connected that across the pins of the Philips Lopt. I've added in an s-correction cap (2x1000pF in series).
Up with the volts.... and I've got about an inch of line scan. Width control makes no difference.
On the plus side, nothing caught fire.
In the word of the Beatles ... "It's getting better all the time"
Shorted out pins C & D on the Philips lopt (where the line lin connects), and put the line lin coil back in series with the scan coils. Removed the S-correction cap, as I'm thinking C76 on the Pye 169 is actually the s-correction cap, just in between windings.
Better results this time, and the width control moves the foldover about a bit.
Can anyone point me in the next direction?
All a bit of a mess at present!
Boost is low at 380V
No boost HT, as there was no HT at the transformer to Boost. HT1 connected to pin 5 of the Philips Loptx.
Looking much more promising now. Width control now working, but there's not quite enough there ....
Harmonic tuning?
Lack of width. Check resistors R85 and 85. Both 4.7Mohms. The resistors are connected in series and are in parallel with feedback capacitor C71. S correction capacitor C74 is 0.18mfd in the 20" models.
Till Eulenspiegel.
Thanks Till. Sadly those resistors I changed before I originally switched on last year, as they were somewhat outside spec.
EHT is somewhat lacking at 12KV. I'd be expecting around 17.5KV ...
Putting 111.11pF (9x1000pF in series!!) across C72A gives me a shade under 17.5KV and a good adjustment of width. Boost HT is also spot on.
I need to repair the stuck tuner and sort out the rapidly dropping height now to see what sort of picture I get. I spy a few Callins to evict!
Looking promising.
Tuner now tuning. Frame now at full height and good linearity after changing C76, the cathode bypass. Sound is fine.
Sadly lacking in video (You can *just* make out some picture) and sync is really weak. Changed the 3 Callins around the TAA700 and the 12V smoothing cap, C56. 12V is a touch low at 11.6V. No change.
Out with the 'scope. Test point E shows video coming in from the IF. Video coming in to the TAA700 on pin 10, about 1.3 V Pk-pk. Oscillograms on the service sheet show 1.5V pk-pk so I'm happy with that. Next to nothing coming out of pin 12. Disconnect the base of the video output transistor VT5, to see if it's loading it down. Still almost nothing on pin 12, so it looks as though my TAA700 has failed. When the set was running on it's original LOPT I had snow with pots of contrast, but I expect the TAA700 died along with the LOPTx. Parts drawer is bereft of TAA700's, so I'll investigate a source tomorrow.
On the plus side, the line stage seems happy with it's new transformer. Valves are not cherrying up, and the transformer is running cool. There appears to be some striations to the left hand side of the picture, but I've still got wires and croc-clips everywhere, so I'm hoping this will sort with a good tidy up of the wiring and some lead dressing.
