Roland TB-303 Bass Synth 1981-1984

SKU: 31497

Sale price$4,499.99


SKU: 31497

An absolute classic that needs no introduction. It has been recently repaired by Robin Whittle who is the man responsible for creating the legendary Devil Fish mod you see on these things from time to time. If you want a Devil Fish mod done, this unit is primed and ready for it. It will of course be an added cost. Unit is in full working condition and would even go as far as saying better functionality than a complete original.

The Rob Whittle repairs to this unit are listed below in his own words.

This machine already has Omron sealed tact switches. These should last indefinitely, which solves the most common problem with TB-303s: dust getting into the unsealed ALPS tact switches.

C20 and C21 are normally 0.01uF, which causes a weedy bass response.  These have been replaced with 0.1 uF capacitors to give a proper bass response, as I do in the Devil Fish. I have retained this, since it is an outright improvement.  If someone wants the weedy response they can do it with EQ.

The CPU, and ICs 9, 10 and 11 are in sockets.  These are high quality machine sockets so they should be fine.

The repairs involved:

1.       Installed three used Toshiba memory chips which have no sign of corrosion.

2.       Fix two large holes in the top and bottom parts of the case on the left side, and three on the top of the top part.   These are now filled epoxy with silver felt-tip pen ink.

3.       Replace the wires to the front panel. 

4.       Replace missing battery cover and positive contact new ones from Sound to Parts.

5.       Replace missing battery negative spring

6.       Dismantle and clean noisy Volume pot

7.       Dismantle, check, clean and relubricate, with lighter Servisol silicone grease, the 6 small pots. 

8.       Mount 6 small knobs a little higher with a spacer.  This and the new silicone grease makes it easier to turn the knobs, which reduces the chance that people will press downwards while turning, which is what causes the internal rotor to cut through the conductive tracks inside the pot.

9.       Install a wire from the Volume pot ACW pin to the ground pin of the Audio Out socket.  This reduces background noise.

10.   Various minor repairs and re soldering of solder joints.

11.   Calibrate all pots for 5.333V reference voltage, VCO tuning and scale, max tempo, interrupt time and filter frequency.

12.   Full test

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