Gene Cafe Heater Assembly Replacement Instruction
Small flat head screwdriver
Cross head #1 screwdriver
Side cutters (preferred) or sharp scissors
Narrow cable tie
New heater assembly. Ensure this is the correct voltage for your region. e.g. for the UK, you will need a 240v heater.
Ensure the Gene is unplugged and stone cold! Start with the Gene Café facing you.
Fully open and remove the clear plastic cover, by pressing in the centre at the rear as shown
If the cover isn’t easily removable then insert a flat head screwdriver between the cover and the case, just above the hinge ‘dimple’. Twist the screwdriver slightly - the cover should pop away.
Remove the two screws holding the metal guard. Use a screwdriver to lift the back edge slightly so you can lift it forwards and away from the Gene (it’s under slight tension). Note the three tabs at the back that slot into the body of the Gene.
Remove the plastic end spacers. On my unit these were clearly marked ‘left’ and ‘right’.
Carefully turn the unit upside down. Be aware it’s going to leak chaff everywhere if its been used for any length of time! Notice the base is held with 8 cross head screws, 6 around the outside and 2 in the middle. Remove all screws - note the 2 center screws are shorter that the others
Very carefully turn the Gene the right way up (remember its in bits!), then rotate so the back is facing you. Lift the top slightly but note the case top can’t be removed completely at this point as two ribbon cables connect the display panel in the case top with the circuit board in the base. However, there should be enough slack to place the top upside down butting against the front of the base so the two cables can be easily removed.
Remove the two cables from the circuit board in the base. Don’t pull the cables – always grip the plug and gently ease away. The top can now be removed totally.
You’re now ready for action! Rotate the Gene again so it’s facing you (the mains cable exits from the back of the Gene furthest away from you – see picture)
Time too identify some important parts! The heater assembly can be found on the right hand side – look for the metal assembly. The heater inlet fan can be seen between the heater assembly and the case. The main circuit board is at the front, while the power supply circuit board is at the back close to the mains cable. Notice the drive shaft that connects with the motor assembly on the left hand side and drives both ends of the drum simultaneously. The foam chaff filter can be seen on the left also, just below the outlet pipe. Since we’re replacing the heater assembly we’ll be spending most of our time looking at the right hand side
Observe the two pairs of white cables leading from the heater assembly. The thicker pair is for the heating element. They are held in place by a cable tie and terminate at the power supply circuit board. The thinner pair are for the temperature sensor and connect to the main circuit board. Also observe the green earth wire held in place by one of the two screws that holds the heater assembly. Pay very careful attention to the routing of these three cables!
Locate the connectors for the heating element as they enter the power supply circuit board. Note that one wire is shorter than the other – on my Gene the slack in the longer wire was obvious. Polarity is (apparently) important, so for identification I suggest you mark the shortest cable and the appropriate circuit board connector (e.g. with indelible pen). For ease, I suggest you also identify and mark the shortest wire on the heater assembly replacement. In my unit, the short cable is the one that plugs into the 3rd receptacle from the case edge. Grip the connector firmly then ease up and away. They may be a tight fit so this may require a bit of effort!
Optionally, you can check the heater element with a multi-meter. If this has failed it will measure ‘open circuit’ (infinite resistance) between the two heater element connectors.
Cut and remove the cable tie being careful not to ‘nick’ any wires. Then untangle the heating element cables from the cable loom and pull free.
Ease the temperature sensor connector from circuit board, again being careful to grip the connector and not pull the cable.
Loosen two screws on inlet fan – this makes removing the heater assembly easier. Untangle the temperature sensor cable from the inlet fan motor cable, noting that it’s folded to fit between the fan and case edge.
Remove the two screws holding the heater assembly (one of which also holds the earth wire). Wiggle the heater assembly and remove it.
Now the heater assembly is free, observe the two small metal wheels that stabilize the drive cog against the metal support. It’s easy to dislodge these while removing or refitting the heater assembly!
Drop the new heater assembly into place ensuring the drum ends are aligned. The easiest way check the drum alignment is to actually try inserting the drum – rotate the heater assembly cog until the ends are aligned and the drum drops into place smoothly. Now double check the two small metal stabilising wheels are still in place!
Fit the two heater assembly screws, remembering to place the green earth wire under the screw on the far right side. Note the earth wire passes through the (now removed) cable tie and follows the case edge.
Tighten inlet fan screws.
Route the temperature sensor cable along the edge of case, folding back a couple of times so there is only just enough lead to reach main circuit board receptacle. Insert the connector into the main circuit board – note it can only be inserted one way round. If you get it the wrong way round the connector can’t be pushed fully in.
Thread the heating element cables through the gap in the metal support (so they are on the opposite side to the heater assembly). Thread the cable tie through its support. Pull the heater cable and earth cable tight so they are not touching the metal heater assembly body, then fasten tie wrap. Cut excess cable tie.
Replace the heater element connectors observing that the shortest cable is attached to the receptacle marked Heater on the circuit board (3rd down from back). Ensure they are fully and firmly connected!
Find the case top and reconnect the two display cables to the main circuit board. Note these can only connect one way round also.
Loosely fit the top and check no wires are fouling. The top should fit snugly into the base.
Carefully turn the unit upside down, and replace the eight screws, noting the two short ones are placed in the middle.
Place the unit the correct way up. Refit the two plastic end spacers, observing the left and right notes embossed in the molding.
Refit the metal guard. I found this was easiest by first positioning the front between the spacers and then easing the tabs at the back into the holes in the base. Ensure the guard fits flush between the two spacers - wiggling the spacers or guard as necessary. Refit the two retaining screws – they should align perfectly.
Refit clear cover.
Done. Enjoy freshly roasted coffee again!
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