Source for SAA7220 and SAA7210

[P Howard]

I have an RCD 855 with a upgraded clock, that has a problem with discs spinning at high speed immediately on turn on. The player has been working fine for over two months, and now this problem has occured. I've verifed voltage inputs from power suppy, and even tried running the clock from the CD players own supply, but the player still spins at very high speed. The clock has been returned to the manufacturer and it works as advertised for him. I made a request for schematics on a previous thread but nothing has turned up at this time. My guess is that either the SAA7210 or the SAA7220 has failed, but my o-scope is in storage at this time and no schematics available, so I have limited testing ability. My only options appear to be changing these items out one at a time. Can anyone recommend a source for these items?

Thanks,
PH

 

[TDA1540]

continuous turning disc and also no display?

(that would narrow the search.BTW i don't think the SAA's are the problem)

 

[Elso Kwak]

TDA1543210, restore the original situation and see if the player works again.
Edit, Sorry I keep addressing the wrong guy. I meant the thread starter, P Howard.

 

[TDA1540]

I have no problem....

 

[Jocko Homo]

Yeah.......no clock......it spins really, really fast. I know. I've mucked up my share.

(OK......only once.........the PSU had a resistor go open.)

Jocko

 

[P Howard]

saa7210 rotel rcd 855

The disc spins, but the display is active. It doesn't provide useful data, but all characters are there and complete.

 

[P Howard]

TDA1543210, restore the original situation and see if the player works again.
Edit, Sorry I keep addressing the wrong guy. I meant the thread starter, P Howard.

The very first thing I did was to resore to original and try the player. No luck there.

 

[Fabian]

Hi PH,

I've got a very similar problem with my Philips CD 650 I think (see: http://www.diyaudio.com/forums/showthread.php?postid=398267#post398267). Display works fine but some controll buttons on the frontpanel don't work anymore.

Donberg (http://www.donberg.ie/descript/s/saa7210.htm) offers SAA7210 and SAA7220.

I'm still not sure what causes the high speed spinning(unfortunately I haven't got a scope). This and the high shipping price prevents me from buying those chips. (maybe we could order togehter?)

Regards, Fabian

 

[Bricolo]

I doubt the 7220 is in cause, since it's a digital filter and has no control on the cd rotation

 

[Fabian]

I just removed the SAA7220 and connected the TentXO directly to the SAA7210. No more high speed spinning! But I still have more distortion at low levels on one channel.

I think I have destroyed something on the oscillator in the SAA7220 when connecting the TentXO (although I don't know how).

PH, if you have the SAA7210/SAA7220 chipset, the clock is very likely generated at SAA7220 and fed from the buffered output (Pin9) to SAA7210 (Pin19). You could connect your clock to Pin19 and see if the problem is solved (make sure that the buffered clock output of SAA7220 is disconnected).

Fabian

 

[P Howard]

SAA7210 and SAA 7220

I'll try that tomorrow and see what happens. I'll probably desolder the pin on the 7220 and jumper the clock to the 7210. I know that the 7220 supplies the clock to the7210 and the 7210 sends it back to the filter, so I gues we'll see.

PH

 

[P Howard]

disk spins problem

No luck on the bypass to the 7210 for the clock. Disk still spins at max speed. I replaced the 7210 and that didn't fix it either. With no schematics for the Rotel 855, progress on this is likely to be slow. All power supply rails appear to be working as advertised, as I took some measurements from a friends machine. Unfortunately I couldn't tear into it far enough to check the transistors and op amps under the transport...

Sugestions?

PH

 

[TDA1540]

I think you should check the supply around the killcircuit.
If something is amiss,it affects the processer(assuming the Rotel PCB is actually a Philipsdesign)
Have had some Philipsplayers on my table where the owners had messed with the killcircuit(mutingtransistors).They showed similar symptoms.(the players.....not the owners)

TDA