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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
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13th Jul 2011, 10:07 am | #21 |
Octode
Join Date: Jan 2006
Location: Borough of Gateshead, UK.
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Re: REGENTONE 194 Convertible
No at present but do have a Dinosaur standards converter which is still boxed and hard to get at at the moment.
As a quick check I connected a Thorn 1500 tuner to the aerial socket which gives some results in Band 1, so was able to prove the tuner in the set is ok. The suspect OA70 is of course the Vision detector diode. A correction to earlier contributions concerns the Plessey tuner type PMI. This is actually a PM 1 type. Cheers, Brian |
13th Jul 2011, 10:22 am | #22 |
Retired Dormant Member
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Re: REGENTONE 194 Convertible
Just about any gemanium diode will do, or a BE BC junction of a germanium transistor. OA90 is equiv.
Last edited by geofy; 13th Jul 2011 at 10:27 am. |
13th Jul 2011, 10:32 am | #23 |
Octode
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Re: REGENTONE 194 Convertible
Fantastic! Cheers Geof. Sure I've got some OA90s somewhere.
Thanks again Brian |
15th Jul 2011, 9:33 pm | #24 |
Octode
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Re: REGENTONE 194 Convertible
I found an OA91 which I fitted but the results were dissapointing, no change to previous conditions.
Voltage checks around the PCL84 didn't reveal anything amiss. It was then I remembered a curious vintage "335 Mica" capacitor wired between pin 1 of the EF183 and Pin 2 of the EF80., marked "30 PC". No idea how it got there but on cutting it we have PICTURES, albeit of the jumbled up mess as one can expect when a 405-line set displays a 625-line negative modulation picture. Perhaps it was put there in an effort to tame the very strong signals available from Burnhope and Poptop Pike in this area? Next I'll dig out the Dinosaur converter to see how it looks when displaying proper pictures. Brian |
16th Jul 2011, 12:26 pm | #25 |
Hexode
Join Date: Apr 2008
Location: Wellington, New Zealand
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Re: REGENTONE 194 Convertible
Hi Brian, have been reading this thread and good to see you are working your way through all the faults..Sounds like you are getting closer to having the set pretty much operational. Those PCL85's can be a pain at times, I had a set that was giving me grief in the vertical department and on the third PCL85 I had a full picture with no cramping. Turns out that the other two 85's were also crook! Can't always trust replacement parts especially when they're used!
Cheers...
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19th Jul 2011, 11:16 am | #26 |
Octode
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Re: REGENTONE 194 Convertible
Very true Glen. I remember when restoring a Philips G6 on fitting a brand new PL519 line output valve it arced internally and glowed bright blue. Turned out the valve was faulty!
Getting back to the Regentone it's clear there's a lot more to do before passing it for "restored". The contrast control doesn't work for example (probably the 10M feed resistor) and, not yet testing the set on a proper 405-line picture they could be sync problems lurking too. I'm very pleased with the progress so far. Brian |
26th Jul 2011, 6:47 pm | #27 |
Octode
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Re: REGENTONE 194 Convertible
I've now got the Dinosaur out and put on test on the known working Philips T-Vette portable. The converter still works perfectly although they were some problems developing with the set, which will be the subject of another thread at a later date.
Back to the Regentone 194! The 10M feed resistor to the contrast control was removed. To my surprise it was within tolerance but having got it out a new 1W replacement went in. The slider of the contrast control, despite an earlier repair was found to have broken from the print, probably due to struggling to fit the back and aligning the controls with the holes. Before this the "pictures" were lousy but there was some movement on the screen. Now to see how it performs on a 405-line picture! Well I didn't expect first class results but things were so bad I could barely make out the timebases wern't locked! The resultant picture when "locked" can only be described as the worst pictures I've ever seen on a TV set! I could just about make out Test Card "F" which was grey and "sparkly", though had I not known I had this playing in the DVD player I may have struggled! The timebases didn't lock solidly. This is more likely due to the video channel rather than a fault in the sync seperator, although I wouldn't be surprised if it's a bit of both. Oh yes- the contrast and limiter controls still don't work. Clearly there's something seriously amiss in the video output stage and possibly the vision IF stage. Any ideas would be welcome. Anyone out there got a spare top panel? Brian R |
1st Aug 2011, 1:51 pm | #28 |
Octode
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Re: REGENTONE 194 Convertible
To rule out problems in the AGC stages It was over-ridden by shorting Pin 1 of the PCL84 video amplifier to chassis. Not unexpectedly this made no difference.
It seems they could also be intermittent troubles to add to the list as on the last test there was a good raster with a very weak response from the IFs in general. I'll try replacing the valves (again!) incase I've fed in a faulty one. You never know! As with any set nasty things can happen if the panel isn't re-connected properly. On one occasion due to getting the pins mis-aligned (easy to do) I was rewarded with a very loud buzzing from the speaker followed by extremely loud feedback. This got louder on hastly switching off for awhile! Thankfully on finding this error no apparent damage had resulted. As mentioned previously any suggestions would be appreciated and if anyone has a spare top IF panel, either dual or single std, handy this would be very welcome. Cheers, Brian Last edited by Focus Diode; 1st Aug 2011 at 1:57 pm. |
8th Aug 2011, 8:26 pm | #29 |
Octode
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Re: REGENTONE 194 Convertible
Thanks to locating the decent camera I'm pleased to upload some better quality photos including the set running.
There's a curious red lead soldered to the print side of the top IF etc panel at R71 in the tuner AGC circuit near the EF183, the other end being a broken bronzed strip. No idea there this is/was supposed to connect to. Brian |
9th Aug 2011, 10:36 am | #30 |
Nonode
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Re: REGENTONE 194 Convertible
Hmmm. Makes you wonder if this could be the answer. Time to dig VERY deep I think!
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12th Aug 2011, 5:53 pm | #31 |
Octode
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Re: REGENTONE 194 Convertible
You're right Tas. I wonder if it was connected to some sort of cable network or something? I've also thought of feeding video and audio directly into the set, by-passing the IFs. Not too sure how to do this off hand.
I'm aware of the safety aspects if this is tried. Cheers, Brian |
12th Aug 2011, 6:37 pm | #32 |
Octode
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Re: REGENTONE 194 Convertible
Hello Brian,
I remember some years ago I fed video from a dvd player straight into the grid of the pcl84 (I think that was the valve??)on a Baird dual standard set via a 0.1uf cap because I had no response from the tuner, the screen of the phono was connected to chassis via another 0.1uf 400v cap (isolation from mains) It was an M6?? series. It worked of sorts. Good luck!! Cheers
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21st Aug 2011, 8:18 pm | #33 |
Octode
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Re: REGENTONE 194 Convertible
Many thanks for your contribution Lee. Very helpful indeed.
Other things have got in the way of further work, but hope to re-commence at the end of the week and will keep you all upto date with any progress. Cheers, Brian |
28th Aug 2011, 8:40 pm | #34 |
Octode
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Re: REGENTONE 194 Convertible
As promised I got back to the Regentone this evening with some great news and was able to prove the tuner and IF stages are now working fine.
Rigging up the Dinosaur standards converter with careful tuning I could make out a negative Test Card C on the screen. Remembering my fitting of a new vision detector diode and Tas' experience with his Sobell ST195 it seemed I'd fitted it the wrong way round. Pretty obvious one may think but perhaps I was confused by the different styles. The original OA70 is black with a red tip with a +, the replacement OA91 is clear with a blue tip. I know the latter is the cathode but I guess the OA70 confused me a little, presumably the +'s the anode? Anyway, reversing the OA91 was a simple matter without having to remove the panel. On switching on here is the result! The CRT is clearly a bit low emission but may improve with use. There's not unexpected top cramping too which could be down to simple mis-adjustment. Remember the PCL8(0)5 and a few components here were replaced. The Test Card "D" geometry is otherwise excellent. Sound is ok and both contrast and vision interference limiter pre-sets work. There's a strong switch off spot, but I see some versions have an added capacitor to prolong the frame timebase a little longer to help prevent this. I may fit this modification to the set. The CRT itself could be responsible being a bit low in emission. The top cramping will be look into shortly. I'm very pleased with the outcome! Cheers, Brian Last edited by Focus Diode; 28th Aug 2011 at 8:49 pm. |
28th Aug 2011, 9:13 pm | #35 |
Nonode
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Re: REGENTONE 194 Convertible
Hey that's now showing a lot of promise and another nice dual standard saved - the more the merrier I say
Looks like just a simple set up of both the top lin and general lin and a tweek to the line hold to remove the foldover on the left and it'll be job done!
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28th Aug 2011, 9:19 pm | #36 |
Octode
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Re: REGENTONE 194 Convertible
Brilliant stuff, well done Brian! That's almost there now. Hopefully as you say the CRT may perk up with a bit of use. I don't know when your set was last in service but it's a safe bet it hasn't seen test card D in a year or two!
Steve |
29th Aug 2011, 2:31 pm | #37 |
Octode
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Re: REGENTONE 194 Convertible
Thanks to you both for the feedback. My comments on No.27 now make sense seeing I had terrible quality unlocked pictures. With the brilliance control at maximum the picture turns negative due to emission. Of course if the video detector diode is reversed it would try and display a "positive" image!
Cheers Brian |
31st Aug 2011, 3:08 pm | #38 |
Octode
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Re: REGENTONE 194 Convertible
Here's an update.
The top frame cramping was indeed due to the Vert Lin Top control needing adjustment. The line lock however looks like a dodgy hold control as attempts to remove the left side shading caused the hold to go altogether and it quite "touchy". Although not nearly as bad as the original height control it will have to be replaced. As a temporary measure the picture was re-centred. There's still some odd problems. With the tuner buttons selected it was impossible to tune down to ch1, yet this could be done when no buttons were in! In addition the aerial socket was found to be loose with an intermittent negative picture (probably AGC lockout). Touch the aerial plug and all is well. A correction is the contrast and vision interference limiter controls still don't work, although the picture is very reasonable allowing for the condition of the CRT. With these problems no wonder I was so baffled earlier on! The set was given a prolonged test run and it functioned beautifully with no major problems showing up. Next to sort out the contrast and replace the faulty horizontal hold control. Cheers, Brian |
1st Sep 2011, 2:36 pm | #39 |
Heptode
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Re: REGENTONE 194 Convertible
Hello Brian. thats looking much better now. although i dont think i would want to work on the board in the first pic as it looks very crowded . cheers neil.
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1st Sep 2011, 7:45 pm | #40 |
Octode
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Re: REGENTONE 194 Convertible
Hi Neil,
The timebase board components are mounted on the underside of the panel, (photo taken with the set on its side), the print and valves on the top. An unusual arrangement but at least the components won't become charred through heat from the valves. Access to the print side is indeed horrible! Cheers, Brian |