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This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Hi all,
I have just worked to life a set of Beosystem 5500. Including Beogram, Beogram CD, Beocord and Beomaster itself, and a Master Control Panel Also
But a weird phenomenom occurs: when testing Beomaster's FM radio, the status reading in the MCP shows false frequency
If I test the radio i.e. on 1 000 MHz carrrier signal (with some 1 kHz modulation), FM radio tunes and locks alright to the signal and the modulating tone is heard. But on the display of MCP the frequency is showed always 2,10 MHz too low...
What might cause this? Is there anything to adjust? In Beomaster? In MCP?
Jouni
Make sure the tuner is correctly calibrated.This is particularly important after replacing the backup battery or after doing repairs to the tuner.Refer to the servicemanual.
Martin
Thank You, Martin
I found in the meanwhile that there is no good enough service manual for Beomaster 5500 available. Only schematics mainly
But the tuner in Beomaster 6500 seems being the same as is in the 5500. So I'm going to proceed in calibrating using it instead...
Hi all again,
A brief update to this problem
Did the alignment of the BM5500's FM tuner as is said in the service manual of BM6500. A bit tricky to do, but I succeeded
But, all the work at least with no affect to the primary problem of MCP showing wrong MHz readings for the FM stations tuned
First I gave it up for a moment
Then I noticed that I had forgot to change the two capacitors (C1 / 47uF/10V and C2 / 33uF/16V) which are on the microcomputer board. I had already been there a while ago when I changed the lithium battery. But was not then paying attention enough to notice these two caps. Perhaps was a bit frightened of the microcomputer, so put it back shielded as quickly as I could
So, some dismantling work done again, carefully though, minding the static electricity, my grounding wrist band attached. Changed the two caps. Put everything back again. And finally power on
Voila! Everything still works!
And voila again, on the top of it, the frequency readings on the display, when pressing the status button on the MCP, are dead on what they should be!
So, a few minutes reset on the computer board, and/or totally being without power, seem to have done the cure. Although I did not disconnect the lithium battery, so static RAM chip being powered all the time. But at least that's what I can think of being the reason of change...
If anyone on the forum can give a better explanation what just happened, free welcome to do so here. At least in the name of growing knowledge of the B&O repairman/repairwoman community...