Nick, so the caps on the Laser PCB 02 were all Nichicon radials except one Philips axial. I replaced them all with good quality Nichicons. I may have misunderstood your previous post. I thought you said if they were Philips to change them.  I didn't notice any difference after replacing them. One of the Philips axials measured low so I was hoping it would help to resolve one of the units.  The Nichicons all measured OK, but I changed them anyway. 

I think I also missed the part in your post about the caps on the Decoder PCB 05. I know I measured them all in circuit previously and they measured OK, but I'll have to double-check them next week to see what type they are. If Philips I will change them.

As far as the power supply, I agree that these regulated voltages are critical. I will try to locate and replace the -18v and -6v regulators with the proper type to eliminate that as an issue. 

I don't have the test disc and laser simulator discussed in the service manual for making alignments, but I'll try to check what I can (motor, RF eye pattern, etc.)

Thanks again for all your help....I'm really looking forward to getting these fixed as one belongs to an important customer and the other is mine... I would love to add it to my system as the sound quality is amazing from what I've heard so far!

And, if you happen to find the training course that would be great!

Best,

Greg

A scan of the training course would make a nice addition to the Beoworld service manual library :-).

-sonavor

Just to clarify Gregg,the caps on the laser pcb 02,are usually Philips axials (33uf)

I like to replace them with new BC/Vishay types as they are the same spec.Nothing wrong with the Nichicons per se,but the Philips/BC/Vishay ones just seem to work better here.It's a mystery?

As to decoder pcb05,this board is crucial as it's where all the clever stuff is carried out.It's usually populated with either Nichicons(22uf radial) or Philips caps.

As mentioned,the Nichicons are fine here,and very rarely have they suffered any age related deterioration,but it can happen.The Philips radial ones,if employed here are usually suspect.

I usually change them all anyway,but I should get out more(not at all at the moment sadly!)

It's worth going the pcb for any dry joints too,particularly around the large ERCO chip SAA7020.In addition to the notorious griplets,there are some other wire link through's too.

Rest assued that when you get these machines working fully,you will be impressed.

I used to have five of them,mad or what?

Nick

I've copied the notes John,but I can't work out how to upload them to the site?

Did I send you the BG4000 training notes btw?

Nick

Hi Nick,

I didn't receive the Beogram 4000 notes but would love to have them. 

I guess we will need to ask Keith. You may have to send them to him for posting in the service library.

John

Hi Nick, I'll check out the caps and solder connections on the decoder board and report back. I appreciate your time and passion for this stuff! I'm the same way!

Take care,

Greg

Hey Nick, Well, I seem to have made some progress! I checked the caps on the Decoder Board 05 and while they are Philips, they all checked OK in circuit. So I moved on to the Servo Board 04 and found that the Philips axial 33uf 16v and 40v caps were all checking higher than normal on my ESR meter so I swapped them all out on the CDX unit that played but would skip after track 5 or so. After cap replacement, I was able to play all the way through a disc twice that previously failed on the later tracks. So, I'm pretty sure that one is fixed! Yay!  Still need to test further, but I'm feeling pretty good about that one.

I then took the power supply board out of the working unit and put it in the other one that I still need the regulator IC's, and it still failed in the same way... disc spins for a few seconds, then the "?" on display. So, I checked the caps on the Decoder board (also Philips) and they checked good. The Servo board caps checked better than the other machine, so I just swapped the servo board from the working machine to this one and it also played perfectly! I also immediately noticed that the disc motor sounded quieter (I think the disc motor is struggling to come up to correct speed maybe with its original servo board). So, I recapped the original Servo board and put it back in this player. Now the disc just spins and spins and spins forever and never stops or goes to the "?". But, it still doesn't track the CD and play. I also noticed the motor doesn't sound as quiet as it did with the other board.

So, I seem to still have an issue on the Servo board. Unless it's some kind of intermittent that just happened to work after disassembly and reassembly. I called it a night instead of swapping the "good" servo board back in the non-working unit to confirm my findings.  I've done the griplets and the caps on the Servo board and checked for solder issues. Didn't see anything else obvious.  I'll try to get back into it, but just wondering if you have any thoughts that might save me some time and lead me in the right direction? The hours are piling up on this one, but I feel like I'm oh so close!

Thanks,
Greg

Progress indeed Greg!

I'd be inclined to put all the good bit's into one machine,so at least you have one working and a sense of achievement too?You can use it for comparison too of course.

You've identified the one faulty servo board,and it seems as though something is awry there since re-capping,as it now behaves differently?Prap's one of the cap's fitted in reverse,or a  solder blob across the print somewhere?

I would replace the Philips decoder  caps too anyway, based on experience.We've all be fooled by components(particularly cap's)testing ok in and out of circuit,but not performing well under voltage.

It's tedious on the decoder board,as there are so many of them,but worth the effort usually.

As you can see from the course notes,the integrity of the data through the decoder is crucial for correct operation,so anything like noisy supply lines can upset it.

Label the known to be good boards,so you don't get them mixed up,and have another good look at that dodgy recapped servo board?

Nick

Thanks Nick, yes I've thought of many of those things, I just didn't spend any more time on it after the 2nd one failed.... got frustrated and went home, LOL!  I agree that caps can check good in circuit and still be bad and was planning on recapping the decoder boards eventually anyway.... but I figured since I think I've narrowed it down to the Servo board I would continue with that one.  I also thought about putting my customer's unit back together to use for comparison, but I'm gonna have to order the correct -18V and -6v regulators for the other one's power supply so I can know that board is working correctly without having to feed voltages into it.  So, that might have to be my next step.

I'll double-check my work on the 2nd unit's Servo board, although as I was recapping it I wasn't too confident it would fix it because only one cap checked slightly off and the rest checked good compared to the other board where the caps were obviously bad. But yes, it would be nice to use the other unit for comparison measurements at this point.

Have you seen anything else beside electrolytics fail on the Servo boards such as IC's, transistors, film capacitors, etc.?

And I hear ya on labeling the known good boards... already done!

Thanks again... I appreciate your time and responses! Will report back soon (hopefully with good news!)

Greg

UPDATE - This morning I tested it and it was back to the original symptom of playing for a few seconds then the "?". So, I pulled the servo board and put the working board back into it and it plays perfectly. I double-checked all my work on the servo board, checked the caps, diodes, transistors, everything seems fine. Made comparisons to the working board and couldn't find anything different. Put the defective board back in and noticed that sometimes it spins and spins and sometimes it spins then stops and gives the "?". So, I don't think anything happened during my repair of the servo board. Maybe an IC is failing? Voltages to the motor board seem good, Have my + and - 12v and the motor is getting like -4.5- 5.0v while spinning. I'm kinda stuck at this point.