Repairing and Rebuilding the Fusers for the WorkCentre® 7328, 7335, 7345 & 7346 series, and 7228, 7235 & 7245 series. Plus, Revisiting the C32 & C2128 Versions of these Fusers
The 7328 family of machines is the final group of models in the “C32 style”. Many of the machines have shown up in the past couple of years in the aftermarket from off-lease machines and such. The fuser is a really good candidate for rebuilding. Good parts are available, the procedure is not too difficult, and the fuser count is easy to reset from the control console.
The C32 style included a few groups of models which were released over a period of about a decade (spanning from 2002 through 2012). The fusers in all of them are very similar to one another and the newest group is no exception. The fuser heat rollers and the pressure sleeves are the same for all of the models. These parts were never spared by the OEM except as part of the complete fuser modules. Fortunately good compatible parts are available nowadays, making rebuilding a profitable choice.
Here’s a list of the 4 versions of the fusers:
· C32 version: 008R12904 / 126K13940 (110 volts), (008R12905 / 126K14890 for 220 volt version)
For: C32/40, (DocuColor) DC1632, C2240, C3535, & (WorkCenre) M24, M32/40, Pro32/40
· C2128 version: 008R12933 (110 volts), (008R12934 for 220 volt version)
For: (WorkCentre Pro or CopyCentre) C2128, C2636, and C3545
· 7328 version: 008R13040 (110 volts), (008R13028 for 220 volt version)
For: (WorkCentre) 7228, 7235, 7245, 7328, 7335, and 7345
· 7346 version: 008R13055 (110 volts), (008R13056 for 220 volt version)
For: (WorkCentre) 7346 only
The DC1632 service manual gives an estimated yield of 100K pages for the fuser. History tells us this is not always true and machines which run a lot of heavy papers don’t even come close to that number. Other literature including the service manuals for the other models neglect to give a stated yield on the fusers.
Almost all of the fusers use the same pair of fuser heat lamps. The only exception is the 7346 fuser which has a double lamp (instead of a pair of separate lamps). For all but the 7346, you’ll find a “Main Heat Lamp” which has a red connector, and a “Sub Heat Lamp” which has a blue connector at the rear end.
The only really significant changes have been in the way the main connector is wired and in that the 7328/7335/7345 fusers have 3 pico-fuses on them, which allow a machine to recognize when a new module is installed. The fuses were absent from the predecessor models’ versions of the fusers. The fuses are found on a tiny “CRUM Board” (CRUM = Customer Replaceable Unit Monitor) inside the rear of the fuser. It seemed at first that soldering on new fuses would be necessary, but as it turns out you can reset the fuser count from the control console. Installing fuses would only be necessary if you needed the fuser to automatically reset the fuser count for a customer in your absence, the way a brand new fuser would. The model 7346 version is unique because it has only one fuse on the CRUM board, a blank spot, and an indexing resistor instead of 3 fuses.
Knowing the pin-out of the large main connector on these fusers is helpful in checking the fuser lamp circuits and the thermistors without needing to disassemble anything. You should have a low resistance path through either of the two heat lamp circuits. If one lamp circuit measures good and the other measures open, then you know that lamp is bad. If both lamp circuits are measuring open, then most likely the fuser overheated and the thermostat will need to be replaced. Thermistors can be measured by setting the meter to 100K ohms, then if you warm up the face of the thermistor with your fingers, you should see the resistance start to drop.
Pin-out – Main Connector (7328 shown)
For C32 version and *C2128 version
Pin 1 = Main Heat Lamp (to red connector)
Pin 2 = blank
Pin 3 = Sub Heat Lamp (to blue connector)
Pin 4 = Front Thermistor (purple wire to white connector) (*blank for C2128 version)
Pin 5 = blank (*for C2128 version: Front Thermistor – purple wire to white connector)
Pin 6 = Front Thermistor (yellow wire to white connector)
Pin 7 = Rear Thermistor (purple wire to blue connector) (*blank for C2128 version)
Pin 8 = blank (*for C2128 version: Rear Thermistor – purple wire to blue connector)
Pin 9 = Rear Thermistor (yellow wire to blue connector)
Pin 10 = Ground Strap (green wire to ground lug on the fuser frame)
Pin 11 = blank
Pin 12 = Return Wire for both heat lamps (black wire coming from thermostat)
For 7328 version and *7346 version
Pin 1 = Main Heat Lamp (to red connector)
Pin 2 = Fuse 3 (F3) (*OR Fuse 1 on 7346 only) on CRUM board (yellow wire)
Pin 3 = Sub Heat Lamp (to blue connector)
Pin 4 = Front Thermistor (purple wire to white connector)
Pin 5 = Fuse 2 (F2) (*OR… goes to nothing on 7346 only) on CRUM board (yellow wire)
Pin 6 = Front Thermistor (yellow wire to white connector)
Pin 7 = Rear Thermistor (purple wire to blue connector)
Pin 8 = Fuse 1 (F1) (*OR to Indexing Resistor on 7346 only) on CRUM board (yellow wire)
Pin 9 = Rear Thermistor (yellow wire) goes to the blue connector
Pin 10 = Ground Strap (green wire to ground lug on the fuser frame)
Pin 11 = Ground / return from CRUM board (gray wire)
Pin 12 = Return Wire for both heat lamps (black wire coming from thermostat)
Measuring components (pin-outs):
- Main Fuser Heat Lamp (+ thermostat): pins 1 & 12
- Sub Fuser Heat Lamp (+ thermostat): pins 3 & 12
- Front Thermistor for C32, 7328, or 7346 versions: pins 4 & 6
- Front Thermistor for C2128 version: pins 5 & 6
- Rear Thermistor for C32, 7328 or 7346 versions: pins 7 & 9
- Rear Thermistor for C2128 version: pins 8 & 9
- **Fuse 1 (F1) on CRUM Board (blows at 50 prints) (7328 version only): pins 8 & 11
- **Fuse 2 (F2) on CRUM Board (blows at 50 days) (7328 version only): pins 5 & 11
- **Fuse 3 (F3) on CRUM Board (blows at end of life) (7328 version only): pins 3 & 11
**Note: The 7346 version’s CRUM board has only one fuse. For 7346 only, the Fuser Reset Fuse (F1) can be measured at pins 3 & 11. No continuity will be found at pins 5 & 11 and you’d be measuring the indexing resistor if you measure between pins 8 & 11.
Following is the beginning of the instructions on how to rebuild one of these fuser modules. The write-up will apply to any of the 4 versions. This article ended up being rather lengthy with all of the photos, so we will have to come back next month for Part 2 to the procedure.
PROCEDURE (see Photo #1 for orientation)
1. Remove the “Front End” cover which is held on by 2 screws. One of them is hiding behind the green pressure tension relief lever (see photo #2).
2. Remove the “Rear End Cover”. This cover is also held on by 2 screws. When you remove it, you’ll see there is quite a bit of wiring squished in behind the cover. Take a note of how it all fits in there. It will help you later when you go to put this cover back on (see photo #3).
3. Remove the Exit Baffle from the top of the fuser, which also has 2 screws (see photo #4).
4. Remove the Exit Pinch-Roll Baffle which is found near the top of the fuser and is held on by 2 screws (see photo #4).
Ok folks! That is all we have time for this month. Next month’s article will finish up the procedure, and we’ll also have a look at how to reset the fuser counters from the control panel. There are several ways to do this, depending on which model you’re working on. Have a wonderful May and we’ll get together again in June.
