ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
After smooth sailing through the 5500 system and the Beocord 5000 & CD50 of this system, this Beomaster 5000 has provided quite a few problems. I disassembled the control panel door to see what the problem was with the Open signal. I discovered the ribbon cable from the control panel was starting to come apart.
The spare Beomaster had a good ribbon cable so I swapped out the entire control panel assembly from the spare to the one I am working on. That didn't solve the Open door signal but I really didn't expect it to. Even with the connector to the control panel completely off the Open signal always seems to be on.
I also tested some of the other control functions, both from the front panel and the MCP. The volume controls and source selection controls all appear to work. The save settings worked on some volume settings I saved. The loudness button does not result in the display showing Loudness lettering. I tried both display units and neither illuminate. The Balance, Bass and Treble controls kind of work. I expected the various bars to change as I increased/decreased the settings but the levels seem be all one way or all the other (full Left/full Right, full On/full Off). By midweek I should have my 3V lithium battery for the original processor board so I'll be able to see if that makes any difference. I will also recap the spare Beomaster preamp board and see if it produces any better results.
sonavor:That didn't solve the Open door signal but I really didn't expect it to. Even with the connector to the control panel completely off the Open signal always seems to be on.
If that means that the actual /OPEN signal pin of IC5 is constantly low (and not a fault in the driver circuit after that), you may be soon looking for a new MM5450 chip. If source selection etc work, the chip is alive and being controlled by the CPU, but may have some blown output pins. Some of the display LEDs (including Loudness) are controlled by it as well.
--mika
tournedos: sonavor:That didn't solve the Open door signal but I really didn't expect it to. Even with the connector to the control panel completely off the Open signal always seems to be on. If that means that the actual /OPEN signal pin of IC5 is constantly low (and not a fault in the driver circuit after that), you may be soon looking for a new MM5450 chip. If source selection etc work, the chip is alive and being controlled by the CPU, but may have some blown output pins. Some of the display LEDs (including Loudness) are controlled by it as well.
Okay, thanks for the information. My parts Beomaster 5000 has an MM5450 chip on it. Interestingly, that board has the MM5450 chip on a 40 pin IC socket where the preamp board I am currently testing has the MM5450 chip soldered directly to the board. I can try swapping the MM5450 chip or recap and see if I can get the second preamp board to work. I already tried the second preamp board though and it is not routing power so it may be best just to swap MM5450 chips.
I am following the route Mika suggested and try the MM5450 (preamp board IC5) from my spare Beomaster. First I removed the MM5450 from the Beomaster preamp board I recapped. I am going to limit any soldering to the replacement chip by installing a new 40 pin IC socket.
Here is the replaced IC5 (MM5450)...I did wear protection when handling it
...and what do you know? The Loudness button works and the door latch control works. A big thanks to Mika for his guidance on this. You saved me a bunch of time by directing me down the right path.
That leaves me with the tuner board still to recap but before that, I played around some more with the System 5000 MCP. Should the Balance, Bass and Treble show incremental bars in applying them up/down like the Volume bars display? On my MCP, the Volume increases/decreases a bar segment at a time on the display but the Balance, Bass and Treble just flash all of their respective segments as I adjust them. Is that normal or do I likely have an MCP problem?
sonavor: Is that normal or do I likely have an MCP problem?
Same with mine no problem
Collecting Vintage B&O is not a hobby, its a lifestyle.
Søren Mexico: sonavor: Is that normal or do I likely have an MCP problem? Same with mine no problem
Great and thanks!I think I am back on track with this unit. I will try to squeeze in time to wrap up this receiver this week. I want to see how it sounds connected to the Beocord 5000 and the CD50.
The 3V lithium battery shipment arrived today. I already have the spare processor board installed and working but I went ahead and installed a new battery in the first processor board I recapped. I will test it out later as I want to move on and get the tuner board recapped.
The tuner board recap was quick and easy. I could have elected to do it first if I wanted to as it swings up and out of the way. There were a few 2.2uF capacitors in the signal path here so I used some Nichicon Muse bipolar capacitors I had in stock.
This unit is ready to reassemble and test. First the plastic air duct and power capacitor holder.
Then the tuner board is secured.
Last, I put the cover back on and the Left/Right Input-to-Output jumpers. I connected my trusty shop Beovox S55 speakers, an FM coax antenna and an iPod Nano (to the Auxiliary input) to give the Beomaster a quick dry run. The tuner works nicely and the sound is very much like the Beomaster 5500 was. Tomorrow I will test it some more. I want to hook up the CD50 and Beocord 5000 to see how well the MCP controls everything.
I started some system testing with the Beomaster 5000 today by connecting up the CD50 and Beocord 5000 I have. The two music sources respond and operate through the MCP 5000 as they should. There is still an issue with the Beomaster built in control panel though. I discovered that the Phono button doesn't always get detected. Most of the time when I press the Phono button the Beomaster will detect a button was pressed but can't tell what and just display "P". Pressing the control buttons via the MCP always work correctly so I will probably have to open the Beomaster control panel up again and see if the problem is just with the button or with the wiring. I suspect the latter but either way I have to open the unit back up again.
This weekend I fixed the Beomaster 5000 front control panel problem. Some of the buttons were interfering with each other (i.e. pressing the up volume would sometimes start tuning an FM station and pressing Phono would yield the Store function instead). I tried swapping the processor board because it was an easy thing to try and the control panel buttons are processed in there. That didn't change the problem so I moved to the next easiest thing, the main wire harness. Even thought there are quite a few connectors on the harness, removing it is really easy. Unfortunately, the fix was not as easy and a different harness made no difference.So the final step was the dreaded disassembly of the front control panel again. I replaced the original panel once because the ribbon cable was coming apart. On the second panel, the ribbon cable was okay and all of the front panel buttons worked prior to reassembling the unit. I have kind of known all along that the issues with the control buttons would mean taking this apart again. It turns out I do have a third control panel to try. The disassembly steps are not really complicated but the execution is a little tricky. Two screws allow the flip down control panel to come loose. The small board the ribbon cable supplies must also be unclipped from the front chassis. The pulley cable for the flip down panel also needs to come off. All of that is straight forward.That results in the flip down control door removed as shown here. The tricky part now is to carefully pop out the plastic retainer clips without breaking any of them. These pictures show the clips already loosened.
With the clips popped loose, the button panel can be removed from the metal cover plate. From here the button board can be detached from the panel for cleaning or replacement. The button board shown in these pictures are already the new board as I took these pictures in reverse.
Reassembling the button board to the front door assembly is easier than removing it but still takes care in getting the clips to pop back in without breaking anything.
Before reattaching the front control panel to the Beomaster, I tested the control buttons. Everything worked with this new button board so the old board had some connection problem somewhere.
When mounting the control panel back to the Beomaster, the spring for the door must have the tab resting in the spot shown in the picture here.
The two door mounting screws (not shown) can then be put in to secure the door and the door pulley reattached.
That pretty much takes care of the Beomaster 5000. It appears to be fully functional again. Both the front control panel and the MCP can operate the receiver.
The Beogram CD50 works well. I had actually already been using that unit with another non-B&O system in my house so I new it was good. The Beocord 5000 plays cassettes really well but when I tested a recording using the CD50 and The Beomaster 5000 the results were poor. There is a problem with fluctuating volume levels in the channels so this unit is not ready for recording yet.I am not going to pursue fixing the Beocord 5000 recording problems right now. My backlog of Beogram 8002 turntables has become quite large and I want those finished by Christmas (earlier than that actually). -sonavor
Outstanding work John.
I can assure you that the Beocord 5000 is a truly great recorder. It replays pre-recordeds really well too.
Jacques
chartz: Outstanding work John. I can assure you that the Beocord 5000 is a truly great recorder. It replays pre-recordeds really well too.
Thanks Jacques. I do plan on getting the Beocord fully working. Right now it actually plays tapes made on other machines very well so the problem it has is in the recording path of the cassette deck. It is usable now as a play only deck but would be nice to have it fully working. My best recorders right now are the Beocord 9000 and my Nakamichi Dragon. The Beocord 8004 is no slouch either. I have only made one recording with the Beocord 5500 and it turned out fine but I would need more samples to compare it to the other decks I use most often (the Dragon and the BC9000).After I finish working on my Beogram 8002 backlog units I would like to get the Beosystem 4500 components working. I have read good reviews of the 4500 system here on Beoworld so it will be nice to get that system functional. I am starting to run out of space though. At some point I will have to make the difficult decision to let some of these go. I am hoping my kids will put some of these restorations to good use.
John