Another step forward.....

Now its been time to assemble my new displayboard (module 8). I used the 7 segment displays from the old board but I had to take them apart to change the segment LEDs inside them. It is a well known problem that the segments go out one by one as time flies. This is discussed in another thread in this forum. The LEDs I have used will light up at a smaller current than the old ones so I needed to change the resistor values to the segments both on module 8 and module 9 (CPU) to get the display brightness right.

When I examined the old displayboard I saw that there was a burn mark on connector P75 pin 12 which is the power feed to the display board. These connectors will wear out and loose their contact pressure and this leads to bad connections here and there. Its always a good idea to replace those connectors to avoid display trouble in the future. The same applies to the CPU module with all its connectors. Bad connections here will lead to control problems and/or intermittent function.

You can see in the pic that I have fitted new Molex KK connectors all the way around module 8 and 9. I have also made a new cable harness with new connectors to module 9 instead of the old and often faulty flat cables.

The top pic shows the old display board.

The bottom pic shows the new display board together with the CPU module.

Restoring the keypads

I have discovered some problems with my keypads on the main control panel and the secondary control panel.

Some of the old metal discs have lost their tension and do not "click" like they used to do when depressed.

The solution I came up with was to use the discs from new tactile keypad switches like MEC 3CSH9 with a disc diameter of 6.5mm ( http://www.mec.dk/switches/switches_under_foil/3c ).

I simply took them apart and removed the little metal disc inside and fixed the discs on the keypad PCB with clear tape. Its a very fiddly job to get them right but its worth it to get the "click" feel back on the keypad.

The results for the main control keypad are shown in the pics.

/Fredrik

Hi all - What a great day!

Been spending several evenings in my workshop lately...🙂

Now it was finally time to do a test run of my restored and rescued bm8000...and guess what...it really works!!!

Felt great!!!...

Now I just have to reassemble the rest of the cabinet and bring it to my living room to see how it performs...

/Fredrik

Great photo thread Fredrik,

I can't wait to see the finished article, your dedication is staggering.

Chris.

Thanx Chris 🙂

It will soon be time to reassemble everything. At the moment Im going through all the adjustments in the service manual to make sure everything is properly set.

/Fredrik

Hey Fredrik,

So how is your amazing rebuild project coming along? How does she sound?

Laurence

Hi Laurence

Its going slowly forwards...havent had so much time lately to be in my workshop. Im going through all the adjustments in the service manual at the moment.

So far I have only tested it in my workshop with a pair of beovox 2702 and it sounds really great and powerful. Im very happy with the sound quality

After reassembly and adjustments I will test it properly in my music room together with my M70 speakers...Ive also got hold of a pair of MS150 speakers to match the set later...

/Fredrik

Mohawk wrote:

Ive also got hold of a pair of MS150 speakers to match the set later...

/Fredrik

Nice😐

Good to hear its all coming together.... albeit slowly...

And nice indeed, some MS150's, you managed to find some congratulations. 🤒

Hi Frederik,

I am in the process of ordering new caps for my BM8000, I noticed in the service manual there are quite a lot of electrolytics and tantalum caps in the signal path.

I took a close look at your pictures, I saw you used some tantals in the preamp, and a film for the 4,7uF on the power amp board?

What did you do with the signal path capacitor types? I am thinking of ordering WIMA film caps and panasonic electrolytics for the 10uF signal path caps (film gets too expensive for me here)

😂