This guide just shows the basics of flat cable replacement for the Switch Board. It is a more difficult repair and may involve drilling holes in the PCB.
Damaged Flat Cable
The glue used to hold the flat cable conductors can lose it’s bond strength with age. Sometimes when removing the flat cable from the display and switch boards, it can get stressed and result in the horrifying condition as shown below. Reinsertion would damage the assigner and switch board and probably short circuit the power supply.
It can be remedied with a more robust solution IDC cable and box headers.
- Right Angle 30 Way box header: Farnell 221-5297
- 30 Way IDC Socket with Strain Relief: Farnell 221-5255
- Ribbon Cable 34 Way 120mm Long: Farnell 297-355 for 1m
- 0.8mm PCB drill bit
Remove Old Connectors
Desolder and remove the existing flat cable headers on the Display and Switch Boards.
Fit Box Headers
Test fit the 30 Way box headers exactly as shown in diagrams below making sure that 3 of the pins at the end of connector are cut flush (only 27 ways are used).
Fitting is not straightforward, it is necessary to align and push the back row of pins into the holes under tension. It will take some careful manipulation to get it into place.
If the pins don’t fit in the holes then it will be necessary to use a 0.8mm drill bit to widen the holes slightly. On this instrument it was necessary only on the Switch Board. A tight fit is good and adds additional strength.
Remove the connectors and fit then again but this time using some superglue to firmly secure the headers.
Refit the headers and solder them in place.
Using the two 30 way IDC cable connectors, make a 120mm long cable as shown below. Red stripe to pin 1 marked by a triangle, one connector up and one down with bumps facing outwards.
The strain reliefs can be used later to tidy up any “slack” once installed in the instrument.
Fitting and Testing
The cable can be tested for fit as shown below, note that the display board has been upgraded with a new display.
The Switch and Display Board can be tested fully before installing back into the JX10 as shown in the picture below.
Copyright © 2017 Super Synth Projects, Guy Wilkinson