PS-77CS Shredder

After around 7 or 8 years of some tough abuse and shredding my Fellowes PS-77CS Shredder has finally given up the ghost and failed on me.

The machine is getting power, but it doesn’t run the shredder motor. There are signs of power going to the device, because it detects win the bin is open and lights up the red light to say it’s open. The light goes off when you push in the Micro switch so this tells me the sensor circuit was working fine and the problem was more electrical as opposed to mechanical.

I did some dismantling of the actual equipment. Fairly simple, lift it up and remove about 10 screws. Open the lid then disconnect the wire attaching the motor to the PCB. I did a quick look around the circuit and couldn’t find any specific issues.

I finally identified the problem, I went to remove the PCB so I could look up the schematics and when removing it the transformer was literally hanging on a couple of threads of copper wire. So it came off easy enough (picture below)

DB-0812D Transformer

The busted transformer which failed. Also seems to be a common problem – not supposed to come off the circuit legs like that. It’s meant to be attached.

I decided to remove it, as it was evident to me the transformer is what caused the problem. For those who don’t know, a transformer receives an incoming voltage in a circuit and then alters it for the output side (either by increasing or decreasing it). In this case, it’s receiving an input voltage of ~220v and outputting it into ~15.6v from what I can find online (these are the specs). I’ve wrote them below if anyone finds them useful.

Input Voltage : 220V
Output Voltage : 15.6V / 15.6V
Dimensions ???? : 8*11 (On other sites, this number translates as “specification” – so I think it’s the size)
No Idea???? : 3+4 (On other sites, this translates as “stitch / work type” – not sure if this means the number of pins)

Now, when researching online, it seems these transformers are commonly fitted to the Fellowes shredder models and seem to be the weak point of them. The point of failure is usually when the shredder falls over or gets banged about a bit. The transformer / PCB are mounted upside down in the shredder motor. So if the unit falls over it can damage it. Essentially it’s dangling on it’s own internals.

A common fix suggested by one user seems to be fitting an M2730 transformer, which is slightly bigger then hot glue it in place so it doesn’t damage it if it falls. I looked up this product and unfortunately it’s a discontinued product. So I may try places like eBay or Farnells/CPC in the UK to try and source one.

In the meantime I have emailed Customer Support at Fellowes to see if they stock spares. I’m more than happy to fit the equipment myself to get it up and working again. Failing that I’ll source one online if they cannot supply. The equipment by Fellowes is amazing. It’s stood up to some tough abuse from myself, but I’d rather not pay £100 for a new shredder if I can fix it myself for around £20

I’ll update this post as I go, hope some of you find it useful and helps you on your quest with your Fellows PS-77CS Shredder or others.

PS : If your from Fellowes, I’ll happily receive a new shredder from you if you offer me one. I wouldn’t complain 🙂

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  • Hola, he leido su artículo, dice usted que la salida del secundario del transformador es de 15,6/15,6v. ¿esto es 4 hilos? osea, dos salidas de 15,6v? gracias

    • Hola. Creo que sí. Sin embargo, creo que solo se necesita una salida. Los únicos detalles que puedo encontrar están en un sitio chino. No estoy seguro si necesita un transformador de salida simple o doble. la placa de circuito solo tiene conexiones para uno. Así que creo que uno está bien

  • Buenas, lo primero gracias por responder. Ahora vamos a lo que vamos. El transformador original si tiene dos salidas independientes(cuatro hilos) pues hay 8 diodos rectificadores normales, osea, esto es, dos puentes diodos rectificadores. En la placa hay dos ne555, (temporizadores de precisión muy conocidos que solo aguantan un máximo de 16v.)

    El problema de éste artículo como tantos más que hay por internet es que publican y comentan sin estar seguro de prácticamente nada. Si fueran dos salidas de 15,6v…¿estas dos salidas son directamente en alterna del transformador sin filtrar? ¿o son una vez filtrada por los condensadores? pues esto es importantísimo , hay que estar seguro, y si no se está, también se especifica. En su respuesta primero me dice que cree que si (que si tiene dos salidas de 15,6v) y acto seguido se contradice….(sin embargo…creo que solo necesita una salida). Osea, lo fliplo., pero bueno ….gracias por publicar esto, aunque los datos técnicos del transformador que es lo más importante no sean seguros.

    • Gracias. Esto es una reparación del HUM. La única información sobre la cual puede encontrar en Internet aconseja sustituir el transformador. Creo que sólo se necesita 1 juego de cuerdas.

      Hasta que consiga un datasheet, realmente no puedo decir el diseño de él. Puedo ir sólo por los componentes. El tranfomer tiene poco espacio libre. Renuncia el voltaje de 230v a 15.6v, así posiblemente incendia las cuerdas. Esto es un proyecto como es una trituradora buena. Por tanto doy la bienvenida a cualquier idea y tomo notas de su suposición

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