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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment. |
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8th May 2019, 10:57 am | #21 |
Tetrode
Join Date: May 2007
Location: Bratislava, Slovakia
Posts: 65
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Re: Another 19 set rebuild
Hi, I managed to finally unscrew the holder.
Left it on windowsill under sun. Used latex gloves and I had more grip, so it came free easily. I upped the photo to the drive folder above.. |
8th May 2019, 2:57 pm | #22 |
No Longer a Member
Join Date: Oct 2016
Location: Maroochydore, Queensland, Australia.
Posts: 2,679
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Re: Another 19 set rebuild
Good idea with the latex.
I have found with the watch holder that squeezing it or gripping it on an end to end axis parallel to the front panel doesn't help as the threads bind more. The better way is to use rubber (as you found out) and get some friction and push the face of the ring that is parallel to the front panel, inwards toward the panel, while twisting, a bit counter intutive but the threads bind less that way. I use a thin sheet of silicone rubber, but there is nothing wrong with latex (unless you are allergic to it !) I've attached some pictures of pocket watches I repaired for my radio. In the end I went with a WWII vintage Waltham type. The other are Jaeger Coulter and another early Waltham and a Swiss made military type. Be wary of the early ones that have cylinder escapement, they are more difficult to keep running. |
20th May 2019, 8:00 am | #23 |
Tetrode
Join Date: May 2007
Location: Bratislava, Slovakia
Posts: 65
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Re: Another 19 set rebuild
Hi,
Nice to see the photos with the watches. Was a struggle to get my holder to open alright but we got there in the end. Re radio, i did more tests last week, no TX out, plenty of drive on meter but nothing more, tried freq counter and my ATU, meter and dummy load. Nothing, plus nothing when switch set to AE. So, as previously discussed, it's time to sort the BFO and take it from there. Also, I've discovered the bottom cover plate is missing from the radio, has anyone a component layout map as I need to identify the few trimmer capacitors on the bottom. I believe the plate had the trimmer ID's on it. Incidentally the B set, when it's powered up, i get a rush of noise when it's on, but as soon as I put a wire on the antenna it all goes quiet. There is some RF out, my freq counter indicated that, but i dont think there is much point to waste time on the B set as it stands. Have ordered the remaining capacitors and resistors this week and will start to restore the BFO in twp weeks as time is short currently. BFO working and TX are the main target now. |
7th Jun 2019, 7:31 pm | #24 |
Tetrode
Join Date: May 2007
Location: Bratislava, Slovakia
Posts: 65
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Re: Another 19 set rebuild
Just a heads up. I replaced another bundle of waxies. I only had 0.1uF 1kv and some of the caps around if stages wrapped up in paper were 0.05uF, although it seems a few were previously replaced. However i went ahead and replaced them.
Main difference is the receive is unbelievably sensitive. Even signal to noise is amazing. Tho i can see this set can easily overload. Other news well , still no bfo working. And no tx. Plenty of drive on meter when keyed on both bands but no actual tx rf. Freq counter verified that too... I have to still replace the resistors and will concentrate around bfo circuit. Today was tiring enough and the improved rx at least was a payoff.. Oh last thing, no tone on mcw when keyed, just clicks in phones. Is there something I need to do as its clearly not generating the tone. Did i introduce a fault? Now to wash the desk off. Its a rather dirty restore! |
7th Jun 2019, 10:57 pm | #25 |
Heptode
Join Date: Jan 2003
Location: Tewkesbury, Gloucestershire, UK.
Posts: 693
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Re: Another 19 set rebuild
If you have plenty of drive on the meter, there must be RF from the driver stage V5A (EF50) as the meter is driven from its rectified output. This indicates that the 465kHz oscillator (i.e. the BFO) must be working in TX mode (possibly the net switch is faulty resulting in the no BFO in RX). The lack of TX output must therefore be a problem in the PA circuit. Do you see the 500V indicated on the meter in the HT2 position when you key?
__________________
Keith Yates - G3XGW VMARS & BVWS member http://www.tibblestone.com/oldradios/Old_Radios.htm |
8th Jun 2019, 5:31 pm | #26 |
Tetrode
Join Date: May 2007
Location: Bratislava, Slovakia
Posts: 65
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Re: Another 19 set rebuild
Hi, thanks for info. I double checked a few things, No HT2 on meter despite a full 575v on the socket. I did restore the psu early on, so at least the running voltages are within reason.
I removed the Net switch, it tested ok. No issues there. I also noticed a wax cap on one side of the bfo pot, so I jumped it with a modern one in case it was this.. No joy. One question, how different is the circuit diagram from the mk3 canadian to british set, im working off the canadian diagram as a guide, knowing well there are differences. Ive yet to do any of the resistors so the more tedious work now. |
8th Jun 2019, 6:47 pm | #27 | |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 14,007
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Re: Another 19 set rebuild
Quote:
Remember that WS19 was designed as a 'mobile' receiver - with a 12- or 16-foot tank-whip as the antenna. So high sensitivity was really, really important to drag the most signal out of an antenna that was 'short' in terms of the wavelengths you were trying to receive. Hook a 50-foot longwire antenna to the front-end of a WS19 receiver and you can easily overload it! |
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8th Jun 2019, 9:04 pm | #28 |
Heptode
Join Date: Jan 2003
Location: Tewkesbury, Gloucestershire, UK.
Posts: 693
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Re: Another 19 set rebuild
As I suggested in an earlier post, it's possible that the BFO is oscillating but off frequency (in my case this was caused by the ferrite core being detached from its adjuster). Can you get your frequency counter probe near the anode of V2B to check that it is close to 465kHz (don't connect directly as the probe capacitance will reduce the frequency or possibly kill the oscillation).
I use the receiver connected to a 132ft doublet without any overloading,
__________________
Keith Yates - G3XGW VMARS & BVWS member http://www.tibblestone.com/oldradios/Old_Radios.htm |
9th Jun 2019, 1:59 pm | #29 |
Tetrode
Join Date: May 2007
Location: Bratislava, Slovakia
Posts: 65
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Re: Another 19 set rebuild
Decided to investigate the resistors . This came up as 56k , though i hazard a guess its supposed to be 47k.
Thats fine i have some decent new ones, but im only raising this as its slightly confusing reading the colours. If you look the body is yellow, rather than a yellow stripe at beginning. Showing my age, this has me double taking the actual values. At the time, was this how they marked the resistors rather that what im used to post 1950s era. Btw no freq op on bfo anode cap when net selected. Also i put probe lower down near coil under v2a. When dial is at 6.00 mhz im getting approx 6.500 ish. Same on other band. One assumes this is exoected. |
9th Jun 2019, 2:12 pm | #30 |
Heptode
Join Date: Jan 2003
Location: Tewkesbury, Gloucestershire, UK.
Posts: 693
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Re: Another 19 set rebuild
Sounds like the BFO may be functioning correctly. One thing to bear in mind is that the BFO injection level is quite low. Try turning the RF gain right down and you might then hear the beat note.
__________________
Keith Yates - G3XGW VMARS & BVWS member http://www.tibblestone.com/oldradios/Old_Radios.htm |
21st Jul 2019, 6:04 pm | #31 |
Tetrode
Join Date: May 2007
Location: Bratislava, Slovakia
Posts: 65
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Re: Another 19 set rebuild
Just a heads up, still no joy with bfo , one issue I have and i guess lack of experience on these sets, is to identify exactly the components. I downloaded a drawing of a mk3 EK Cole set which I have yet the position of some of the components is completely different. Even the coils underneath are different. I guess thats as much as expected as there were so many versions of this set.
Re BFO. Im too tied up with work currently to tear into the set, Im also somewhat reluctant to make matters worse. Like I said the AM rx is insanely good compared to my R209 so I have somewhat respect and fear too to alter the set too much even for a repair. Has anyone a set of drawings or component layout for this set that may be closer to what I have. Oh, on the "B" set, just an observation, when its powered up, I hear the familiar "rush" of noise in the phone, but as soon as I touch the antenna socket it quietens. I also hear a lot of mechanical noise coming back into the phones when i adjust the tuning. I wont investigate too far into this, but has anyone experience of the B set working to know what i should expect. Incidentally there was no RF out when testing on dummy load. Not that i would tx it as is but I was not sure what state it was in as found. I know this will roll on into winter for sure.. |