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Thursday, October 14, 2021

Beogram 8000: Adding Quick Connect Capability for the Workbench Beogram 8000 uC

Now that I have my Workbench Beogram 8000 up and going I restored and checked out some Beogram circuit boards.

Two Beogram 8000 boards turned out to be real trouble.
Their uC (microcomputer boards - PCB 2) were not functional and they had power supply issues. Perhaps the two problems are related.

In attempting to evaluate the faulty boards I decided to use another Beogram 8000 board to check out the 1IC1 uC devices of the two boards. 

I tried swapping the PCB 2 Microcomputer assembly first but that did not result in a functional Beogram 8000.  

Next I tried swapping just the 1IC1 microcomputer IC.  I also tried two other uC devices.
That did not work either...even when installing the devices in a supposedly working PCB 2 assembly.
I know from working on a lot of these Beogram 800x turntables that the uC devices are pretty durable and it is quite unusual for them to be faulty.  So to have three bad uC devices didn't seem likely.  I needed to do some more testing of those ICs.

Changing the 40-pin uC devices is time consuming. You have to be very careful with them (protect against ESD) and installing them in another 40-pin IC socket is not all that fun.

What I really needed was a (easy) way to install them in my Workbench Beogram 8000.  In my known, working PCB 2 assembly.  The key word being easy.

I decided to modify my Workbench Beogram 8000's PCB 2 to be able to perform quick swapping of 1IC1.

I installed this 40-pin ZIF socket and socket receptacle assembly.


It required a little bit of Dremel surgery on the PCB 2 metal case but I decided that it would be worth it for the ease of swapping uC ICs.

Here is the original 1IC1 uC device re-installed in the new quick connect/disconnect socket.





























Does it still work?

































Yes...just as good as before.

Now I am ready to check out those suspected faulty 1IC1 devices from the other boards.

The first suspected 1IC1 device is from a board that the owner said the uC was doing strange things.
It would illuminate but sometimes show various combinations of LED segments.
Installing it in my Workbench BG8000 tester the suspect 1IC1 comes up in Standby mode.
That seemed good at first but nothing happens when I pressed the control panel buttons.  The uC appears frozen in that Standby mode.

















I believe that confirms the uC IC from that board is indeed bad.

My other two 1IC1 devices however, tested good.
Here is one that I had already jumped the gun and marked as faulty.
Installed in the Workbench BG8000 it performs perfectly.

















I feel good about my quick connect/disconnect socket for this Workbench Beogram.
I can see adding a couple of these sockets to one of my Workbench Beomaster 8000 uC boards.

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