Revox B226-S transport problem

Bernhard · 13th August 2005, 03:58 PM

Hi,

just got one and there is some part missing, between the puck and the arm that presses it onto the CD.
Anybody knows how it looks like ?

The problem is that the arm touches the puck directly and the arm does not lift the puck entirely when opening the disc tray.

By the way, CDM1mkII and single crown S1 chip.

And it uses AD7528 dual multiplying D/A converter as attenuator for the variable output.

Is this a good idea ?

Lourens · 14th August 2005, 11:28 AM

Quote:

Originally posted by Bernhard
just got one and there is some part missing, between the puck and the arm that presses it onto the CD.
Anybody knows how it looks like ?

You can find the service manual here
Probably the nylon sleeve on the driving pin is missing or severely worn. A complete and well aligned tray has to load very, very smoothly!

Quote:

Originally posted by Bernhard
By the way, CDM1mkII

Are you sure it's not CDM1?

Lourens

Bernhard · 14th August 2005, 01:24 PM

Thanks for the link, here is a pic of the transport.

It is CDM1 mkII like in Philips CD880. It made me wonder too, I also expected CDM1

There is another problems, the backlight of the LCD is very very dark and the loading tray was totally blocked first.

Parallel to the belt there is a slot (?) where a pin with white plastic moves. Around the pin was a worn out black rubber.
This slot is wide where the pin is when tray is open, it becomes more narrow in the middle and widens again to the end, but not as wide as on the beginning. The white plastic is just to big to fit except on the beginning.
Now I replaced the white plastic with something else and it works so war except there is still a little resistance when closing the tray and it starts moving back and forward in circles until I push it a little to close. I don't believe there is a mechanical damage to that slot

Lourens · 14th August 2005, 05:16 PM

Quote:

Originally posted by Bernhard
It is CDM1 mkII like in Philips CD880. It made me wonder too, I also expected

IMHO this it not original. This could very well explain the loading problems because the distance between puck and top plate (or rather: the spindle plateau) is very critical.

Quote:

There is another problems, the backlight of the LCD is very very dark

A very common problem on Revox cdp's. On eBay you will find the necessary replacement bulbs.

Quote:

and the loading tray was totally blocked first.
Parallel to the belt there is a slot (?) where a pin with white plastic moves. Around the pin was a worn out black rubber.
This slot is wide where the pin is when tray is open, it becomes more narrow in the middle and widens again to the end, but not as wide as on the beginning. The white plastic is just to big to fit except on the beginning.
Now I replaced the white plastic with something else and it works so war except there is still a little resistance when closing the tray and it starts moving back and forward in circles until I push it a little to close. I don't believe there is a mechanical damage to that slot

This 'white plastic' should to be the nylon sleeve i mentioned. Normally it's fitted with a black rubber O-ring and is the bearing on the driver pin of the selenoid lifter which engages exactly into the guiding groove of the cd drawer*. Just replacing it 'with something else' will not do, i'm afraid. This self lubricating precision nylon sleeve is responsible for the smooth ride your Revox deserves. Find a new one or make one yourself. I used a rather similar sleeve used in the ordinary (slow!) cdm1 drawer mechanisms you will find in nearly all first generation cdp's with Philips inside. It's outer diameter too big, so you have to carefully machine it to the exact size.
This all has no relation at all with the red arrow in your picture!

*in German: "Nylon-Hülse am Mitnehemerstift des Magnethebers in die Führungsnut de CD-Schublade".

Good luck!

groeten
Lourens

Bernhard · 14th August 2005, 06:11 PM

It is original CDM1 mkII, CDM1 could never fit there.

I think something is missing where the red arrow points to.

Bernhard · 14th August 2005, 11:56 PM

The transport works.
Backlight is FL and should have 110Vac.
But it is not very bright.
When I increase voltage to 150V, yes there is a pot

, it gets better but for short time only, the voltage starts to drop over a few minutes and the display gets dark.
On the primary there is an op amp coupled by a cap.
I already changed the cap and the AC voltage on the op amp output is stable.
The step up transformer gets hot.
Can it be the FL is dead and starts making a short after warm up ? There are no other parts.

Lourens · 15th August 2005, 09:03 AM

Quote:

Originally posted by Bernhard
[B]It is original CDM1 mkII, CDM1 could never fit there.

Yes it will. Your B226 is just an beefed up (S1) and externally restyled 226 (black facia and wooden side boards) using the same chassis as all first and second generation Studer/Revox cdp's like B126, A725 and A727. All are fitted with cdm1, so i still think the mkII is a modification. Compare yours with this standard B226:

Bernhard · 15th August 2005, 10:52 AM

Yes it looks the same except the prozessor pcb is a little bit different.
I downloaded the sevice manual and that is also for B226 & S.
And guess what, the inverter ( for backlight ) section was missing.

Does standard B226 also have 1541A S1 chip ?

Maybe they changed CDM1 to mkII later on in production, the base where the mkII is mounted looks original and will not fit for CDM1, same with servo board.

Any idea where to get that backlight foil ?
I adjusted to 112Vac and it is stable but not very bright, is that normal ?

Lourens · 15th August 2005, 11:33 AM

Quote:

Yes it looks the same except the prozessor pcb is a little bit different.

Like this ?
In that case the 226S looks more like a beefed up B126...

Quote:

Does standard B226 also have 1541A S1 chip ?

No.

Quote:

Maybe they changed CDM1 to mkII later on in production, the base where the mkII is mounted looks original and will not fit for CDM1, same with servo board.

Quote:

Any idea where to get that backlight foil ?

Search the web or eBay (past biddings), sometimes look alike FL's were offered there, my Studer A727 does not need one yet, and i did not bookmark the website of the maker.

Quote:

I adjusted to 112Vac and it is stable but not very bright, is that normal ?

Yes, diying backlits are very common, also with FL -- replace it.

Lourens

Bernhard · 15th August 2005, 11:45 AM

Yes it is exactly like the B226s on that picture and got single crown chip.
Also in Philips players some used CDM0 other CDM1, maybe REVOX ran out of CDM1, the player is from '89.
I have 3 single crowns and two of them are very good on left channel and the other on right channel.
Now I think about building a DAC with 2 chips and only use one channel of each chip.
Same with 6 another single crowns, some have also only been good on one channel but never on both.

13th August 2005, 03:58 PM	#1
Bernhard diyAudio Member Join Date: Apr 2002 Location: Munich	Revox B226-S transport problem Hi, just got one and there is some part missing, between the puck and the arm that presses it onto the CD. Anybody knows how it looks like ? The problem is that the arm touches the puck directly and the arm does not lift the puck entirely when opening the disc tray. By the way, CDM1mkII and single crown S1 chip. And it uses AD7528 dual multiplying D/A converter as attenuator for the variable output. Is this a good idea ?

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14th August 2005, 01:24 PM	#3
Bernhard diyAudio Member Join Date: Apr 2002 Location: Munich	Thanks for the link, here is a pic of the transport. It is CDM1 mkII like in Philips CD880. It made me wonder too, I also expected CDM1 There is another problems, the backlight of the LCD is very very dark and the loading tray was totally blocked first. Parallel to the belt there is a slot (?) where a pin with white plastic moves. Around the pin was a worn out black rubber. This slot is wide where the pin is when tray is open, it becomes more narrow in the middle and widens again to the end, but not as wide as on the beginning. The white plastic is just to big to fit except on the beginning. Now I replaced the white plastic with something else and it works so war except there is still a little resistance when closing the tray and it starts moving back and forward in circles until I push it a little to close. I don't believe there is a mechanical damage to that slot

14th August 2005, 06:11 PM	#5
Bernhard diyAudio Member Join Date: Apr 2002 Location: Munich	It is original CDM1 mkII, CDM1 could never fit there. I think something is missing where the red arrow points to.

14th August 2005, 11:56 PM	#6
Bernhard diyAudio Member Join Date: Apr 2002 Location: Munich	The transport works. Backlight is FL and should have 110Vac. But it is not very bright. When I increase voltage to 150V, yes there is a pot , it gets better but for short time only, the voltage starts to drop over a few minutes and the display gets dark. On the primary there is an op amp coupled by a cap. I already changed the cap and the AC voltage on the op amp output is stable. The step up transformer gets hot. Can it be the FL is dead and starts making a short after warm up ? There are no other parts.

15th August 2005, 10:52 AM	#8
Bernhard diyAudio Member Join Date: Apr 2002 Location: Munich	Yes it looks the same except the prozessor pcb is a little bit different. I downloaded the sevice manual and that is also for B226 & S. And guess what, the inverter ( for backlight ) section was missing. Does standard B226 also have 1541A S1 chip ? Maybe they changed CDM1 to mkII later on in production, the base where the mkII is mounted looks original and will not fit for CDM1, same with servo board. Any idea where to get that backlight foil ? I adjusted to 112Vac and it is stable but not very bright, is that normal ?

15th August 2005, 11:45 AM	#10
Bernhard diyAudio Member Join Date: Apr 2002 Location: Munich	Yes it is exactly like the B226s on that picture and got single crown chip. Also in Philips players some used CDM0 other CDM1, maybe REVOX ran out of CDM1, the player is from '89. I have 3 single crowns and two of them are very good on left channel and the other on right channel. Now I think about building a DAC with 2 chips and only use one channel of each chip. Same with 6 another single crowns, some have also only been good on one channel but never on both.