Beogram CD 6500 stand-by issue

6 replies
J(
Offline
judgefilip (archived2)
Bronze
Posted September 27, 2015 at 02:45 GMT
#2203312

Hello everyone,

My Beogram CD 6500 has developed a strange issue. As I remember correctly it used to work like this: when listening to CDs and switching to another source for example radio, Beogram used to go into pause and it still does, but after longer period of time, when still unused, it used to go to standby. Right now it stays in pause indefinitely, moreover when I listen to the radio and switch my BM 6500 off, the BG CD stays in pause! Pressing Control -> CD -> St. by on MCP doesn't do anything. I have to press CD, then CD starts playing and I can turn the whole system off either via MCP or directly via BM, BG etc. Also I've noticed that sometimes the stand-by indicator on the BG CD doesn't light up, nonetheless the BG CD continues to function as it should - the tray does open, pressing play will initiate playback, and then st. by indicator is back on!

The player has been fully recapped one year ago, including small reset caps near the ICs. I was especially careful not to cause any ESD damage to ICs. It is otherwise fully functional and reads every single CD I want to play.

Does anybody know what can cause this abnormal behaviour? ICs contain masked ROMs so I hope they're ok, as replacement won't be possible...

Thanks a lot!

Filip

DI
Offline
Die_Bogener
Bronze
Posted September 27, 2015 at 08:47 GMT
#2203313

When the player goes into standby instead of playing the cd, then there was a read error, that means the drive itself or the controller has still a problem.

When the player does not switch off, then there is a time out error in the digital unit, telling us, that there could be a problem with the 5V regulators or power supply. That would also cause the error above.

Check the 5V regulators, both ! Surprisingly tone of them changes the voltage to 5,5V... and causes digital problems. Seen several times...

The player has severe problems with cracks in the solder, seen every time when there was a problem. Especially around the wires/cable connectors...

J(
Offline
judgefilip (archived2)
Bronze
Posted September 27, 2015 at 15:10 GMT
#2203314

Thanks for your quick response!

I've measured DC voltage across pins 2 and 3 of 7805 voltage stabilisers and for IC1 it is exactly 5V and IC2 gives 5.144V. I've also checked the player with my other Beomaster 7000 - it behaves just the same so the problem does not seem to be the dying SAB8032 in the BM6500 itself. I've also switched the jumper inside the transformer to 240V, but it didn't help.

I've decided to record a short video to show the exact behaviour of the BG. It looks like the problem occurs only when switching from the CD to Radio. Notice how the track number indicator stops to blink after 2 seconds. When switching from CD to Phono track number indicator on the CD player will continue to blink and therefore shutting the system off will also put the BG CD to st. by. When switching from CD to Radio the CD player freezes. There seems to be an issue with Datalink commands handling so again I suspect the IC4 MAB8461. This would be the worst case scenario...

[View:http://www.youtube.com/watch?v=9F5jYYywo2A:800:0]

 

DI
Offline
Die_Bogener
Bronze
Posted September 28, 2015 at 17:42 GMT
#2203315

What software version is in the BM6500?

Since the cd player has no real problem to play, it looks a little bit like old software bugs...

I'm not sure, i have seen version 1.4 1.6 and 1.7 on the BM65000.

You have a eprommer?

J(
Offline
judgefilip (archived2)
Bronze
Posted September 28, 2015 at 22:24 GMT
#2203316

Currently: BM6500 SW 1.5, BM7000 SW 1.1

I happen to have a SW 1.7 EPROM file for BM6500 that Dennis from this forum sent me once. I never actually managed to update it. Do you know if the 27C512 chip is suitable to write such file? I don't want to mess with the original EPROM chip, just replace it with another one. I have a friend who owns a programmer and is always willing to help.

Do you possibly have the newest version of BM7000 software?

Thanks again for your help.

DI
Offline
Die_Bogener
Bronze
Posted September 29, 2015 at 16:09 GMT
#2203317

The 1.7 Software will fit on a 27512 Eprom, 64KByte. No problem, that's original.

Try it, maybe it solves the problem.

The latest BM7000 software is V1.3 i think... :)

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