Early KW2000 Transceivers
EARLY KW2000 TRANSCEIVERS
Its quite difficult to trace the timeline of the early KW2000 radios, but as far as I can tell looking through the KW magazine adverts there were at least 4 distinct variants of the MK 1 as KW fiddled with the design ;
* The very first production run was quite short and ran from late 1963 until around May 1964. These models had the meter design from the prototype (used on the earlier boatanchor radios as well) and a very simple dial escutcheon (the prototype had no escutcheon). You can see that KW were clearly aiming at the emerging HF mobile market in this picture. These early variants are quite rare and I have not seen one for sale recently.
* The 2nd production run from May 1964 until Summer 1965. These models had the meter and escutcheon that was used on the later 2000A but were not in a 'G line' case and had the light blue front panel. The picture makes it appear as a slighly better looking home station ! I have 2 of these
* The final MK1 KW2000 production period ran alongside the 2000A in 1965/6 and had a small G line case (with the inspection lid and no mobile mounting bracket fixings). Early models of this period had the light blue front panel and later ones had the dark grey front panel (same as the 2000A). My friend Richard G3UGF believes there may have also been an option to buy a separate G Line case to improve the 'look' of the older models.I have one of these with the dark front panel.
The VFO dial on the 2000 / 2000A has a readout that just about manages a resolution of 2kHz and the odd (and unobtainable) slow motion drive has a tendency to wear so that you set a frequency and then the dial moves a little..called 'KW lumpy VFO syndrome'. There aren't enough 200kHz segments to cover 15m and 10m - another compromise. KW quickly added the 'separates' to the G line - the KW201 receiver and the 'Vespa' transmitter. Both of these were updated to become the KW202 RX and KW204 TX, but even into the 70's these lacked basic 'transceive' capability and had to be netted onto the same frequency. The KW 1000 linear amplifiers and antenna tuners have endured and many are still working in ham shacks to this day.
LATE MODEL 'G LINE' 1966/7 KW 2000 - FEBRUARY 2008
Took delivery of these exceptionally clean 1966/7 2000 MK1 (and another PEP METER) after seeing an advert on Gumtree (London). The radio had not been bodged in any way and was even partly tested by the seller using a GDO on RX. When I spoke to him he was convinced it was up to 6MHz off frequency. I was not so sure unless all the heterodyne crystal had been mixed up, which would be very odd for an unmolested radio..after all old GDOs can be wildy inaccurate, or perhaps he was reading from the wrong scale.
Before I ran it on my own PSU I spotted a few of the nasty black Hunts caps..I changed all of them and the normal resistors that go high, although I was surprised to see some resistors already changed. The PA 6146 looked a bit sad so I put a NOS 6146 in to be on the safe side
After cleaning the switches and pots it came up straight away with no issues (and spot on frequency). The TX on 80m gets great reports and I can get over 60W peak out of it easily. Cosmetically it was also in great condition and a quick clean of the case showed no real need for a repaint..its super clean
EARLY MODEL 'PRE G LINE' KW2000 (X 2 !) MAY 2017
Took delivery of 2 early 2000s in May 2017. The serial numbers are close (299 and 313), probably 1964 vintage. Came from the same eBay purchase complete with Power Supplies. One of these radios (on the left) had been stripped down and partially restored, the other had some new parts fitted but very shabby. The'Pre G line' cases are very thin and poor quality, you can see why KW moved up to the better quality cases.
There was a big difference in the state of these two radios, the one on the left had been very well cleaned up - someone had worked hard on it. With the unrestored KW2000 (right) I started to encounter some new issues...for some reason the ferrite slugs in some of the coils had been exposed to damp and had jammed rigid - what ever I tried (oil, wd40 ete etc) I could not move some of them. If was ever going to align the radio properly after restoration I had to do something. The only option was to remove the coils and very carefully try and chip the core out. I ended up using a drill and a 6mm tap and took it very easy so that the formers were not damaged. the worst was one of the broad band coupler coils with has 2 slugs. This radio also had a lot of component changes and not all of them the correct value..ARGHHHHH, the bodgers..why dont they get it right or leave it alone?. At least he didn't use an electric drill on it! . The radio was extremely dirty with quite a few dry joints, wiggle a suspect component and it comes off in your hand. Surely no one used it with the very odd parasitc choke?.its just a coil of wire. As with my other projects I removed the valves, crystal, relays, vox, PA and the front panel so I could clean both radios up. These are just some of the issues I have faced fixing KW2000s..
Wrong value or out of spec resistors on the screen grids and anodes of the RX RF amp and IF amps. Check all cathode resistors. Only a few electrolytics in the actual radio and only one on the HT
ALL HUNTS black axial capacitors must go. No matter what you think about the radios performance, they are truuly awful . They were identified as a problem in TV and Radio sets as far back as the 60's with some estimating a design life of only 5 years- if you find them they must be replaced. They are mainly present in earlier KW gear.
The rubber band holding ferrite slugs in the coils can turn to cement - they will never turn again. First time I have seen this.
Broken central spigot on the 6146 final in one radio..and yes, I did plug it back in wrong as I hadn't noticed..lucky there was no bang, it just upset the heater balance
VFO faults - low output or only oscillates at the bottom of the band..if the resistors checkout OK (you can test a lot of them with the valve out and measure resistance between the valveholder and the 150v HT or ground), it may be nasty HUNTS bypass caps inside the VFO. I test the units with 6.3v and 150v on an external power supply and a scope. The difference in output with new caps is staggering. The VFO has to come out though ! This pic shows the location of the caps (one is hidden behind the resistor)...I have snipped the leads to tack on 2 new caps and check the VFO operation before the final fix.
My NOS resistors may only last 30mins before failing.
RF choke in the cathode of the 2nd TX mixer OC ...now I know why I had no power out. Also checked the RF Chokes in the Driver stages, often burnt but still sort of working. Replace
Always replace the PA grid coupling cap and check all PA components for signs of stress
More dry joints than I had seen in a while (in both of them). This was mainly due to botched component changes and mods rather than KW assembly faults...and the odd Hunts black capacitors that had been left were changed.
The strange purple wire in the wiring loom near the Mic socket of Mk1 2000s...doesn't go anywhere..checked the other radios..same wire just with a bit of sleeving over the end...odd
Very poor carrier suppression - more HUNTS capacitors, leaky diodes (only 2 of them) can be replaced with modern BAT85. One of the 453 or 457kHz carrier cystals has drifted into the filter passband or vice versa!.
Strange AGC performance will probabaly be due to poor / leaky RX IF amp valves (both 6BA6), or the EF183 RF amplifier.
The PA driver 6CH6 can take off without its screening can...same as Heathkits !
The rear 2 bandswitch sections wear and mean the PA coil taps may not connect reliably. Its not so much the contacts, the rotor part is worn where the shaft goes through..I think replacement is the only solution - but difficult
Complete realignment (premix crystal oscillator is often way out on a least one band), and dont forget that nail varnish remover to soften the glue on many of the coils wound directly on the ferrite slugs..you will never ever align the radio properly without it !...the premix crystal osc drive is critical for the TX, you wont notice it as much on receive. Put a scope on the EF91 crystal osc output and tune each band for maximum
The mechanical filters can still work after 53 years!
STRIP DOWN PICTURES, FRONT PANEL BACK ON, CRYSTALS POLISHED !
OH DEAR ! ANOTHER BODGE NEW CAPS SLEEVED TO FIT PSU
After an extensive strip down, deep clean and renovation both Mk1 radios are working well on the low bands. The PSUs also got a complete refurbishment, I replaced all the capacitors, resistors and associated components - the left and middle pics above show how bad things had got and how Mr Bodger fixed it (no capacitor mounting bracket). I replace all capacitors with modern small components, but make up proper fixing hardware (right). I reconditioned the paper cone loudspeakers and baffles and replaced all the tarnished screws (including new cabinet feet). My research on the case colour of these early radios threw up some odd results - very early models may have had a darkish blue case, although it appeared this quickly changed to a light hammered grey. The bezel is part of the case and cant be easily removed (although on one of mine the rivets had been drilled out of the PSU bezel so it could removed). I rubbed down and test sprayed one of the cases with hammerite smooth silver which gave very pleasing results and was close to the original colour. Click on the pic above for a larger image of this fantastic restored radio. The microphone is a c1970 rebadged 'Turner + 2 CB/ Ham power mic', all metal made in japan and picked up at a rally for £10 - works fine.
MISSING C19 CAPACITOR IN EARLY KW2000 MODELS
In the course of restoring KW2000MK1s and early KW2000A I discovered a little undocumented KW mod. ALC wasn't fitted until 1967 on the later 2000A models and without it there was danger of splatter if the mic gain was set to high. KW must have decided to cut the drive down a bit by removing the cathode bypass .01 cap (C19) in the TX Amplifier (V3) but never took it off the schematic. When I first discovered it I blindly put the cap back (thinking Mr Ham Radio Bodger had removed it)..and immediately had more drive...and splatter. So far 3 of my early radios have this cap missing. Good old KW trying to catch me out !
LATE MODEL MK1 KW2000 - MARCH 2017
This scruffy and rather shabby later period Mk1 looked very sad on first inspection. It is period correct with a single 6146 PA, in the small chassis, better 'G line' case and with the strange VOX BOX. This odd box is shoe horned into all the early 2000s on a large multiway connector in what looks like a real bodge job. Oddly there is an unused valve holder hole in the chassis under the VOX BOX of these radios - so it looks as if some last minute design changes were made!. Although KW called it an option the radio won't go into transmit without this unit. I think its a pity that they had this extra unit fitted , the prototype 2000 didn't appear to have it and looked very nice indeed. The MK1 2000 had an odd production run from late 1963. By December 1964 KW was advertising the improved KW2000A model but continued to market the MK1 until the end of 1966 (advert on left from August 1966) . The only explanation I can come up with is that KW stuck with the MK1 as its smaller size and lower output power made it better suited to mobile operators. It was not in any KW adverts by the start of 1967. This example is from the later period of production as the front panel is the darker colour of a 2000A
This 2000 came from a museum that had closed - it was bought untested for display and had not been used since sometime well before 1993.
I left the very dirty PSU to one side and checked the radio first. A thorough and deep clean normally reveals the the first few problems. Nothing for it but to remove the front panel, the vox box, all the valves, relays, PA cover and get to work with soapy water and a stiff brush (not quite the soaking that some Collins and Heathkit restorers advocate). The aluminium knobs are particularly hard to clean up but can be brought back to reasonable condition. As expected some issues soon came to light. The PA Anode RF choke had been replaced - badly, the 6146 looked in poor health, the VFO slow motion drive had failed and a different Jackson one had been grafted on. The case was also partly repainted (?) in the wrong colours..radio ham bodgers should be kept well away from spray paint!.
I changed the components that normally give problems (screen and anode resistors / bypass capacitors), plugged it in to a spare KW PSU and it came to life !. After a touch of alignment and a rebuild of the PA I dared to transmit..and after a little bit of adjustment we had good power out on 160, 80 and 40m. It drifts less than my 3 other KW2000s and by all accounts sounds fine on 80 and 40m, and how did the mechanical filter manage to last over 50 years?.
The 2000, 2000A and Vespa used a strange Jackson (?) slow mo drive and a dial cord to turn the VFO. - these drives are unobtainable in the 21st Century. Although Jackson drives are available again, to the best of my knowledge this type has not been remade with the precise dimensions to drop straight in. What's odd about it is that its just a concentric drive, the pulley sleeve is the output..there is no shaft at the rear. The most common failure mode is that the ball bearings fail of break up and the central shaft is often jammed. The VFO still tunes but really quickly !. I had to find a solution and had a spare 2000 VFO to practice on - I found I could use a new Jackson 4511DAF drive (as used on the 2000B) with some small homemade aluminium brackets. It was fiddly to make them and I spent a few hours with the needle files until I was sure it would work. When I make another set for my Vespa drive I will make them a fraction smaller..live and learn.
The dial cord only has a light load and works fine on the outer part of modern drive. I did not have to make any mechanical changes to the radio or the VFO to do the work..so the mod can reversed if another drive turns up. A previous owner had already drilled extra holes in the front panel, my mod didn't need them -radio ham bodgers should be kept away from electric drills !. Once released from the main chassis the VFO and drive can be removed as one complete unit. The hardest part was measuring and getting the dial cord on. I came up up with a work around for that as well - I pretensioned the dial cord spring with a thin pice of wire and got the dial cord as tight as I could, then with it all assembled I cut the wire holding the spring and it pulled the cord very tight..needs must. If you look carefully at the pics you can see the two little holes I drilled in the big VFO pulley to hold my wire tensioner..neat !!
The finished radio looks brand new - case repainted in 'Ford Polar Grey', bezel repainted in 'Ford Dove Grey' and the new slow motion drive now looks and works as it should. I re-capped the Power Supply (which did have Hunts capacitors fitted), I just dont trust 50 year old electrolytic caps. That also came up OK and after a repaint the pair look absolutely fantastic.