PART 2: Karl Dawson’s MK2R Music Maker 30 Serial Number 2594
This Machine first started its life as a MK2 16 selection 78 RPM machine, at some point after 1955 it was returned to the Dock Road factory in Lytham and converted to a 30 play 45 RPM machine, the original mechanism was built in the UK under license from the USA company Wurlitzer, but the 30 Play conversion kit was designed totally by Ditchburn, as far as we know Wurlitzer never made a 30 play 45 rpm mechanism.As mentioned in the last section of part 1, I decided that a strip down was required as a lot of the parts were coated in old solidified grease and needed to be cleaned and lubricated. First i started with the credit units The first is the original credit unit that was modified a credit removal coil and relays this unit adds 1 credit for every 6d inserted and every time a record is selected a credit is removed. this unit also was modified with relays to switch the motor run and the amplifier mute circuits. also additional capacitors had been fitted to de-bounce the coils.All the capacitors needed replacing as they were old type electrolyte caps and were showing signs of aging and failure, also the relays were replaced as the contacts were in bad in a bad state, you can see that the back relay that mutes the amp between plays has a burnt contact, that is because the original relays were not rated at 300vdc and the Valve HT took its toll over time.
Add and Deduct a Credit Unit
Front( before restoration )
Back( before restoration )
Photo Ref: DB301 Courtesy of Karl Dawson.
Photo Ref: DB303 Courtesy of Karl Dawson.
Front( after restoration )
Back( after restoration )
Photo Ref: DB302 Courtesy of Karl Dawson.
Photo Ref: DB304 Courtesy of Karl Dawson.
All the mechanical parts were removed and cleaned, the star wheel was lubricated using a fine Graphite powder do not use oil as this will cause dust to stick to the shaft and will prevent the wheel free running. the caps were replaced, and the relays were replaced with higher rated and sealed units.
3 plays for 1 Shilling Unit
This Unit provides 3 pulses to the credit unit above on insertion of a shilling, This unit took a bit of work to restore it uses a GPO uni-selector that has a wiper contact that moves 1 position for every pulse on the step coil and on insertion of a shilling it will step across the 25 positions from start to finish. some of the contacts had dirt and corrosion on them so it took a bit of work to clean them, the unit uses two capacitors, both these needed replacing, the first one acts as storage for the coil and the second capacitor prevents the credit coil on the unit above from dropping out as it steps between the 25 individual contacts, these units fit onto the side of the cabinet.
Photo Ref: DB305 Courtesy of Karl Dawson.
Photo Ref: DB306 Courtesy of Karl Dawson.
( before restoration )
( after restoration )
Photo Ref: DB307 Courtesy of Karl Dawson.
The Rubber turntable mat had over time become hard and brittle and lost its grippy surface, I thought it was going to be difficult to find a replacement, but i noticed that the Ami R84 mat was very similar and thought it may need some trimming to fit but when it arrived i found it was identical in size to the original, but the bottom had fixing protrusions, so it was a simple process of slicing these off flush with the surface and gluing the mat to the turntable, i cleaned the platter and hub chrome with metal polish and it was as good as new.
Photo Ref: DB308 Courtesy of Karl Dawson.
Photo Ref: DB309 Courtesy of Karl Dawson.
Photo Ref: DB310 Courtesy of Karl Dawson.
Photo Ref: DB311 Courtesy of Karl Dawson.
Photo Ref: DB312 Courtesy of Karl Dawson.
The Record Stack
The record stack had become stiff over time due to the oil and grease solidifying, so i decided to strip down the stack and clean and polish each tray, the grease was difficult to remove but underneath the chrome was still top quality so only metal polish was used to bring back the shine on each stack, on reassembly i used a few drops of 3in1 oil between each washer and tray and also in the spring linkage. the trays were exceptionally free moving after this.
Photo Ref: DB313 Courtesy of Karl Dawson.
Photo Ref: DB314 Courtesy of Karl Dawson.
Photo Ref: DB318 Courtesy of Karl Dawson.
Photo Ref: DB319 Courtesy of Karl Dawson.
Photo Ref: DB320 Courtesy of Karl Dawson.
Photo Ref: DB321 Courtesy of Karl Dawson.
The end of record trip switch and the cam cycle start switch was in bad condition, so replaced the trip switch with a new sensitive micro-switch, these switches are used in coin slots so take very little tracking pressure to activate the contacts. and the cycle start switch was replaced with a heavy duty micro switch
Photo Ref: DB322 Courtesy of Karl Dawson.
Photo Ref: DB323 Courtesy of Karl Dawson.
Photo Ref: DB325 Courtesy of Karl Dawson.
Photo Ref: DB326 Courtesy of Karl Dawson.
The Tonearm trip assembly was stripped down the solidified grease was removed and the bearings made free, and some light oil was applied, the supports and mount were cleaned and re-painted black. a tag strip was added to the support using a spring clip to allow for easy servicing. and the unit reassembled and tested with the start and trip positions on the record.
Photo Ref: DB327 Courtesy of Karl Dawson.
Photo Ref: DB340 Courtesy of Karl Dawson.
Photo Ref: DB341 Courtesy of Karl Dawson.
The Final Test
Before putting the Mech back into the cabinet, i decided to first test the mech on the trolley, connecting everything together. it also allowed me to set up the record start and end trip positions easily.
Photo Ref: DB333 Courtesy of Karl Dawson.
Thank you for watching, there’s another restoration starting soon.