I started my Pioneer PL-12D modification with a bit of hesitation because the turntable was already in a relatively very good condition considering its 45+ year old age.
When I acquired Bobby, his RCA plugs had a bit of corrosion on them them, so I decided to cut them off and replace them with new plugs. After cutting back the cable insulation, it was obvious that the corrosion extended down the length of the stranded copper. That’s when the modification began.
The Pioneer PL-12D came stock with a wood-looking vinyl wrap. I used a heat gun to remove the wrap and replaced it with a 1/42″ thick Walnut veneer and finished the wood with a Danish oil.
I never liked how the stock 5-foot fixed RCA cables with grounding wire or the 115 volt power cord looked, so I removed them and replaced them with jacks mounted to the back of the turntable.
For the power cord, I wanted to use an IEC C7/C8 combination, as I felt that they look very clean. The power inlet in an Interpower C8 that mounts with two metric screws to the back of the turntable and is wired to an internal circuit board. I bought a 6-foot C7 power cord on Mouser to connect the turntable to the wall supply.
For the RCA jacks, I used rear mounting Switchcraft phono connectors with gold contact plating. The RCA jacks are wired to an internal distribution post that connects to the tonearm cables.
I installed a Keystone binding post with gold contact plating for grounding, but I ultimately decided to ground through the left channel ground – which has worked very well.
For the tonearm, I replaced the Ortofon cartridge that was mounted on the headshell with the Nagaoka MP-110. I wasn’t going to replace the stock headshell cables, but one of the connectors broke off the right channel cable and I wasn’t satisfied with the replacement that I made, so I replaced all four cables with Jelco Litz wire cables. I replaced the tonearm cable with Cardas tonearm cable from KAB Audio. The tonearm cables wire direct to the distribution post that the RCA jacks also mounted to. I used Cardas Quad Eutectic solder for all the audio solder joints.
The Pioneer PL-12D come with four internal spring which are stuffed with a foam-like material which helps dampen vibrations. Over time, this foam dries out and the springs are left to bear the weight of the top cabinet without the support of foam. I replaced the four springs and the four footpads with rubber grommets made specifically for electric motor vibration dampening.
The drive belt on this turntable was dry rotted and cracked when I first acquired the table, so I purchased a new belt. I also used a fine grit sandpaper to gently remove leftover belt residue on the platter and drive pulley. It should be noted that turntables are essentially precision machines — meaning that you want to run at 33.3 RPM and 45.0 RPM on the dot — and that any rubber belt residue left on either the pulley or platter could through off the drive ratio and cause RPM issues.
The project wrapped up and Bobby’s restoration was complete. About two or three months later, I started to have some odd RPM fluctuations. It turns out that the oil port was gummed up and the bearing oil wasn’t reaching the motor’s sleeve bearings.
The electric motor on these Pioneer PL-12Ds is a simple shaded-pole c-frame motor held together by two through-bolts. I disassembled the motor, cleaned and lubricated the sleeve bearings and reassembled. Problem solved.
Bobby doesn’t really see too much play these days. He has a retirement shelf in my basement.