Last updated: May 12th, 2010.

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These are items I have bought second-hand, some were in a bad way or incomplete. Some are restoration projects, others just collectibles to love. (Click on image for full sized in new window)

Building new drive electronics for the Technics SP10 MK2 direct drive turntable motor.

When Jean's Radio & T.V spares sadly closed forever at the the end of 2006, I acquired among a huge pile of components that she gave to me, a new-old-stock motor for the legendary Technics SP10 broadcast turntable.
To become part of a turntable, it needs a 3-phase drive system, and a quartz phase-locked-loop servo control system. This project has a special page here, and web-forum here

ReVox B77 Mk1 stereo tape recorder

The B77 ¼" ½-track reel-to-reel is so famous, a photo is not necessary. This 'Mark 1' version I got for R200 (about $26), and it looked in a sad way. Yet again, I neglected to photograph it before revitalising it - the photo on the right is after I fixed it up. This one had paint splatters across its face (why is that so common with vintage audio - what do people DO with them??), the Record and Monitor knobs were broken off, and the cabinet in front of the handle had been heated to the point of distortion and blistering (a desk lamp perhaps?).

Electrically it seemed to work, but after 10 minutes it started smoking & smelling terrible! No surprises - the Rifa class-X capacitor across the mains had caught fire. Getting to it requires removal of just about everything, so a good opportnty to clean it all out. Someone had replaced the tape-drive-control PCB with the most recent version - which is nice, but also shortsighted, since it isn't directly compatible with the original B77's tape tension switching, it could never have worked properly as I received it! The previous owner must have suffered all kinds of poor starting, and tape snatching. Some rewiring of the reel-size switch and added resistors fixed that.

The Record and Monitor switches on all ReVox B7** components are almost always broken when you find them now - a fragile switch dolly - although the switch itself remains fully intact.

Repair here requires drilling a hole directly in the centre of the remainder of the snapped-off dolly (a specially carved wooden centering jig makes this possible), inserting a short steel rod, and fabriating a new dolly. The dollies I machined from strips of acrylic plastic, cut from a cracked tuntable cover. Once painted, they are indistinguishable from the originals (photo above shows my replacements), although not as resistant to finger wear as the genuine metal-coated originals.

The melted cabinet required sanding down, to flatten the warps. I tried filling it with polyester body-filler to restore the dimples, but the polyester reacts with the ReVox plastic and makes it gummy. Instead, I fixed its looks by carving out a rectangular recess along the entire top front, and slotting in a strip of 35mmx10mm aluminium extrusion. Apart from the fact that no other B77 has an aluminium 'fringe', it looks like it came out of the factory like this! All the original Nextel had to come off - easy enough as it dissolves totally in ordinary methylated sprits. Recoating in Nextel is just too costly, so I used satin-black aerolak. Very dark grey would have been preferable, but I could not find any in a matt finish.

I replaced the 1979-vintage red record LEDs: the originals - as with all of that time period - don't have much brilliance, and their colour is rather yellow.

SABC-SAUK broadcast turntable

This "Dok Viljoen / Mark 3" broadcast turntable came from the SABC in Auckland Park (Johannesburg). You can see the little "SABC/SAUK" ownership badge on the top left corner. I don't know which studio this one was used in, but here is a photo of the Radio 5 studio around 1984, showing four Mark-3s . Not visible, because of the records on the platters, is the platter mat which was a brilliant blue! These turntables were also in use before the move from the original SABC/SAUK "Broadcast House" building in Commissioner Street.

These turntables were made by the SABC workshops and are exceptionally heavy (25kg) and durable - look at the size of the platter and bearing below. (The SABC is no more the capable, vibrant organisation it once was, but now a mismanaged, bankrupt joke, with no such manufacturing facilities.)
The drive system is by three idlers, only one being put into service at a time by one of three solenoids. The main bearing incorporates a fourth solenoid, which can lower or raise the platter, connecting it or disengaging it from the rigid and oversized rubber mat. When the platter is lowered, the rubber mat rests in the raised bezel surrounding the platter, and is stationary. Raising the rotating platter causes it to connect with and lift up the rubber mat, thus providing "instant start".

Mine is missing the motor, and arm tube - but the arm bearing is intact. I have a ReVox G36 reel/winding motor (Papst, 3-phase induction motor) that will work here. The original Bodine motor was synchronous, but a quartz PLL on the Papst motor will make an excellent substitute.

The last two pictures are the speed control panel. I'm missing the right-hand control panel that performs cue operations.

Here is a drawing of the missing control panel that I plan on making as a replacement. I'm hoping someone can tell me the functions of the pushbuttons 1-4.

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March 2010 Update: "JD" has recently acquired two Dok Viljoens of his own, from the Port Elizabeth SABC studio, and sent me photographs of the control panel for me to clone. Also of the Papst motor in his, although I think that this motor is a late upgrade or modification.
Now I know the button functions! 1: Cue. Lifts the platter without driving it - the idlers remain disengaged. This allows the track start to be cued up by hand, listening over headphones. 2: Stop. Disengages the idlers, and lowers the platter. The rubber mat rests in the bezel and cannot be rotated even by hand. 3: Ready. Engages the drive idler, keep the platter lowered, but rotating, ready for instant start. 4: Start/Broadcast. Raises the rotaing platter to instantly start the record rotating, and switcches the audio over to "on-air".

The ReVox G36 (A736) is unusual (unique?) for a 'domestic' tape recorder of the 1960s for having a three-motor direct drive transport with solenoid activation, and 'almost soft-touch' controls.

When the pushbutton switch assembly on one of mine broke many years ago, I replaced it with a system of eight relays that mimicked the mechanical locking/interlocking safety action of the original pushbutton system, and provided equivalent electrical switching for the motors and solenoids. 'Feathertouch' micro-switches gave it a 'modern' feel and look. In the delirium of my hubris, I also sprayed the entire faceplate black - I was a teenager and wanted a black Teac X2000. Little did I know what I already had.

But now, I like the idea of restoring its looks (original appearance as in the photo above), AND giving it extra performance in the tape drive control circuitry. The aim of this project is to replace the electro-mechanical pushbutton assembly (or my old relay substitute) with original-look buttons, but with microprocessor derived logic, contactless electronic switching of all motors and solenoids, electronic reel braking by means of the winding motors with tape motion sensing, and full IR remote.

Since I have other projects jostling for my time, this one is at the end of the queue. But send me your comments, if you have opinions on the idea. More info on this project here

Nakamich 550 Dual Tracer portable cassette recorder
Very DIRTY and un-cared for when I received it. The first thing I did was to completely disassemble it for cleaning. For all the reputation Nakamichi has, this one has a spectacularly UN-impressive tape transport. I have better engineered transports in cheap mono portables from JVC and Sanyo. A transplant may be in order one day! A better bet may be to replace the tape transport with a Compact-Flash-based digital transport. The 550's analogue amplifiers and layout are still rather nice.

The reel hubs have been given new rubber tyres - from a Panasonic VCR service kit, and the capstan bush ought to be replaced (a job for a rainy sunday). The belts are still good - I suspect replaced not too long ago by previous owner.

The cassette compartment door is missing, so a replacement will have to be constructed. Also, the plastic of the front panel seems to have some sort of blistering disease. This is easy enough to remove by abraision, but with it will go the printed lettering for the record level controls. So I still need to create a new printed plastic facia to install behind the two rotary knobs.

When I got it, the mic mixing knob was missing and the shaft bent. Curiously, when I opened it up, there was the knob - rattling around inside! The pot shaft was fairly easy to straighten by putting it in a stationary lathe and using the 'back end' of the tool to bend the shaft.

Marantz 6170 (1978)
2 speed direct drive turntable. (now a 4 speed)
This was in a very bad way - very badly scratched, smashed arm, glue spilled on it. I bough it JUST because I wanted a platter for another project. but when I looked more closely at it I decided it was too special to hack up for donor parts.

So it's been gutted: the injection moulded chassis I filled with lead shot and polyester resin which added a good 3kg to the plinth mass. Then resprayed with "Krylon Champagne Nouveau", which is NOT an exact match for the original, but I like it better. The original was an almost 'pink' metallic. This is now a golden-yellow Champagne.

The original arm was broken - the bearing carrier cracked - and very messily glued. By chance I have an almost identical NOS arm (except without the moulded Marantz logo) in my box of collected spares.

I took out the permanently wired in audio and mains cables and made these both socketed connections. And I added 16.66 & 78 RPM to the DD control system, mainly so I can play my extra-long play CBS 16's. The motor is of Matsushita origin, and seems to be the same as used in the first Technics SL1200. The switch to select 16 or 78 I put under the platter - accssible just by lifting the rubber mat - so the original cosmetics are not altered in any way.

You can see the interior - showing the casting resin - here

And the small piggyback circuit board to enable 16 and 78 RPM here

It came with no headshell, so I made a replacement out of parts I had lying around - DIY headshell construction here

Well it's finally finished - fully revivified, and here are the photographs (click any image to enlarge)

Sansui SM-12A (1963)
AM-Stereo + FM-Stereo (outboard MPX) receiver. 2xECC85 + 2xEL84 SE class-A audio output.
Required general clean-up and a capacitor & valve replacement. I replaced the co-axial volume potentiometer with a dual-mono tone/vol pot from a Sharp car cassette deck. Since the Sharp pot had 2 different resistance track wafers, I disassembled two of these pots, and swapped the wafers.
Sharp is a useful company! Their car cassette deck pinch rollers fit the ReVox B710 & B215 !
Still needs a tuning eye.

UPDATE:FEB 2010
I managed to get two 'magic eyes' from Mr Valve. They are not the correct 6GE12A - which is impossible to get NOS. But I did get a 6AF6 and a 6AD6, still quite costly at R400 each. These eyes are unusal in having dual independant shadows. The ones I got lack the triode section, but I will make a simple FET circuit to substitute for that.

Grundig CD 7500 (1984)
Based on a Philips CD-303, but with improved DAC & Decoder board (NO Sony chips in here!), and a special uniquely Grundig grounding layout.
I traded this for an old 20" TV set.
It was broken when I got it, not reading discs at all. But a replaced 6n8 capacitor on the servo board restored it to full functionality. The cabinet was very badly scratched, but is getting re-painted, and new wood side panels (instead of original plastic).
It has the highly regarded Philips CDM-0 mechanism & optical unit, and TDA1540 D/A converters, which are also reputed to sound special. It really does sound GOOD!
The early Philips players have a reputation for slow track searching (20s for a track search I have read), but this one is not particularly slow - it will find any track on a 'long' cd in under 7 seconds. Maybe it has upgraded Grundig firmware in the servo microprocessor?

I replaced the wired-in AC power cord and wired-in audio cable with sockets. Inside there was no space for an AC receptacle, so this went into a die-cast box on the back.


3 RCA sockets? Maybe a hint of getting SPDIF from the SAA7000/SAA7020 !

Below are just more photographs of items I have collected, with no special story. Many more to come as I find time to photograph them and upload the pictures.

	"Selectomatic" 1960 valve/tube radio/phonograph, made by Tesla Radio Corporation of South Africa.
	Webcor Model 201, made in the USA around 1958 ¼-inch ½-track mono tape recorder, bidirectional record and playback. 9.5 & 19cm.s-1
	Studer D740 Compact Disc Recorder, made in Belgium, 1990; actually a Philips CDR-850 in another skin, with slightly different firmware and balanced audio + AES/EBU I/O. The wooden side cheeks are my addition instead of the ugly rack ears.

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