Board Locations in the Analogue Organs

By the time WERSI moved into the Digital era., excepting keyboard and displays, most main boards were located in a central electronics "cage". To assist owners of analogue organs, I have shown the probable locations of most of the main boards. I have included active links to any technical manuals that can be downloaded.

Click on the buttons above for the organ layouts. (Requires Javascript)

DX Series

Known Problems

Hybrid Power Amplifier OM961

A common fault is on these organs is the failure of the OM961 power-amplifier module.  This device is now obsolete, but a suitable replacement is the SSE-10, manufactured by Obantec for Juke Box components.  It is marketed in the UK by Sound Sense Electronics.

Battery Backup DXSeries, (Also CX1, CX2)

These instruments were built in the late 1980's, so if you have never changed the backup battery, it will need replacement. Even if the instrument work fine, the battery will have corroded and started to destroy the printed circuit board. Located on the MST CPU board, the battery is a 2.4 volt 3 pronged, 2cell battery, similar to those used in Central Heating timers. a 2.4v Varta (Varta 2/v150H) is a suitable replacement. In the UK they may be obtained from batterytastic Tel: 01914274577. Remove the old battery, giving the board a good clean with isopropylalcohol or similar solvent, as the old cells whisker corroding the PCB track. Wear an earth strap to avoid static. Keep the time to a minimum to avoid losing the memory while the battery is removed from the board.

Datacasettes

I sometimes get cries for help when people lose the original datatapes for the DX series organs. Usually a result of the battery having died on the processor board (See above). So far I only have datafiles for the DX300, 400 and 500. If anyone can supply original data for the DX5, DX10 and DX350 then please drop me a line.

DX300 I enclose an mp3 file for the DX300 datacassette (2.3MB) This was supplied courtsey Anton Houtrie.

DX400/500 Datafiles for the Standard data and Sounds 86 (18KB). These are datafiles and not audio. They should be loaded via the RS232 port, see my Connections page.

SpareParts

Orion, Helios, Zenith, Galaxy

Electronic Organ Constructors Society UK.  A quantity of Tab Switches, Stops and Rockers for WERSI analogue organs may be obtained from them. [see article by Don Bray]. 

Cosmos

Or try these other sites with Buy Sell Sections

Some tips on soldering

When I set out to build my WERSI Beta, I decided to spend the extra money to purchase a decent soldering iron having a temperature controlled bit.  Having spent so much money on the kit, I did not want to spoil it by not having reasonable soldering equipment.  Of course if one is carrying out a repair job at home, one is not likely to purchase an expensive iron for the purpose, but it does mean that one should take extra precaution.

Why is Temperature Important?

Soldering is the bonding together of two metals; this is normally a bonding between the circuit board track and a component. When one solders it is necessary to raise the temperature of both items to a temperature above the melting point of the solder, before applying the solder.

However, if the temperature is raised too high, it upsets the bonding between the circuit board track and the board.  This causes the track to lift and one may end up doing more damage than one is trying to repair.  It is for this reason that a temperature-controlled bit is preferable, as the chance of causing damage is considerably reduced. 

Removal of a faulty component: -

1. .                    Tools, a number of items can be found useful in removing faulty components.   Items used in dentistry are also useful in electronics, namely the dentists mirror and hooked probe.  The mirror handy for seeing behind components on the board, whilst the probe is useful in removing plug in IC’s as it can get between the pins enabling the component to be eased out without undue strain on one spot.
   
   
2.                     The normal tool for unsoldering has the appearance of a small bicycle pump.  The plunger is compressed against a spring and the nozzle held against the joint, which is reheated with an iron.  A button releases the plunger causing the solder to be “sucked” into the device.  Care needs to be taken, this device is good at removing bits of Printed Circuit Track along with the solder.
   
   
3. .                    Avoid overheating of the board when removing a component.  Soldered IC’s are best removed by cutting the pins off first with side cutters and then removing each pin separately.   Removal of an IC intact is feasible but difficult on single sided boards, it is almost impossible on double sided boards.

An aid to making good solder joints: -

1.                     There needs to be a reasonable mechanical bond between the items being bonded.  Bear in mind that it may be necessary to remove the component in the future, and this is harder once the item is soldered.
   
   
2.                     Double sided printed circuit boards often require a solder connection on the upper (Component side) of the board, not only on the underside.  It is preferable not to insert components fully into the board, but to leave them raised by about 1mm (1/16^th inch)
   
   
3.                     Clean and tin the iron before soldering.  Cleaning is best done when the iron is hot as this melts any residue flux on the iron.  Wipe the iron on a clean damp sponge
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4.                     Hold the tip of the iron to the junction to be soldered so that heat is transferred to both components.  For most components the iron should be held to the joint for 2-3 seconds before applying the solder.
   
   
5.                     Apply solder sparingly and remove the iron from the joint the instant the solder has been applied to prevent overheating of the PCB and the component.
   
   
6.                     A good joint is indicated by the solder having a shiny appearance with a thin sliver of solder between the board and component lead covering the pad.