Beomaster 8000: Installation of New Keypad Ribbon Cables

I recently received the lower front panel of a Beomaster 8000 for the installation of new keypad ribbon cables. The original ones had developed some bad contacts in the attached headers.

I designed proper replacements and had them custom manufactured:

I extracted the original ribbon cables and installed the new ones:

Then I open up one of my Beomaster 8000s and tested the keypad with the new cables:

Beolovely!! All keys worked as they should and so hopefully this restoration will come to a successful end soon!

Beomaster 8000: Repair of a Ripped Off Keypad Ribbon Cable

I recently repaired a ripped off ribbon cable in a Beomaster 8000 that connects the volume rotary encoder to the microcontroller board. I thought I was done, but the front panel came back, now with the frequency encoder cable broken off. The hot glue that I used to fix it in place had come off from the cable, and subsequently it broke off during the rigors my customer's restoration effort put on the solder points:

At least this time I was able to reuse the cable in its full length, so I could simply remove a bit more insulation and solder it back in. I removed the keypad PCB, cleaned the solder points and then did the soldering:

Then I glued it on with epoxy to the PCB back, hoping this will be more durable:

After that I reattached the PCB using new (they should not be reused after taking them out) 3mm retaining clips and nylon washers to protect the PCB. Then it was time for testing. I put the panel into the Beomaster 8000 that I am currently restoring for another customer and turned it on. I tested all keypad buttons and both encoders, and everything seemed to work properly. I hope this was the last time I worked on this particular panel and this 8000 will finally be happy!

Beomaster 8000: Test of Repaired Front Panel Ribbon Cables

After reattaching the severed ribbon cable of the Beomaster 8000 front panel and cleaning the contact pads of the program and source keys, I tested the panel in one of my own Beomasters. It worked nicely, all buttons responding precisely and the rotary encoders doing their job. Here a couple of impressions:

Time to send this panel back that it can continue serving in its own Beomaster!

Beomaster 8000: Repair of a Broken Off Keypad Ribbon Cable

I am assisting a Beomaster 8000 restoration. Today I received the front panel of this unit with an almost completely severed keypad ribbon cable. These ribbon cables easily break off if the Beomaster is opened a few times. Often the glue that fixes the cables to the keypad PCB fails at this age and the 24 gauge leads take the brunt of the cable flex every time the panel is lifted. They only survive this a few times and then they break off. If only one or two break off, this can be fixed by inserting a bit of copper braid and with some flux and solder the connection can usually be restored. However, in this case most of the leads were broken off:

So it was time for some microsurgery. I removed the PCB. This required to cut the original retaining clips, which are of the non-removable type. They can easily be replaced with 3mm retaining clips, so this is not an issue. There is an earlier blog entry that details this procedure.

Once the board was removed, I cleaned up the solder points and then prepared the cable. I had to extend the length a bit since I needed some 'meat' to rebuild the connections. If the cable is too short it is difficult to put the panel into service position with connected ribbon cables. I made eight extensions from an old computer ribbon cable:

Then I soldered them to the prepped ribbon cable leads:

A bit of shrink tubing of the proper color finished the job:

Then it was time to solder the ribbon cable back in:

I also embellished the leads of the other ribbon cable with some solder to stabilize them. They were still intact, but I could see that they also had started breaking off.

Since I was in there, I decided to also clean the contacts of the keypad switches. They usually are a bit oxidized. The oxide layer can easily be removed with a fiberglass pen. This shows the P7 switch before cleaning:

And after:

I did the same with the contact springs. this pic shows one before. The dark spot is the oxide.

Unfortunately, I forgot to take a picture of the cleaned spring pad. They also get nice and shiny after the fiberglass pen treatment.

Then I put the PCB back in using 3mm retaining clips and #4 nylon washers to protect the PCB:

Then it was time to glue both of the ribbon cables to the PCB to protect the cable leads from further bending events. I used hot glue (like the original setup):

That should do it!