Naim CDi servo board problem
- Thread starter iqpi
- Start date
iqpi
Member
UPDATE:
Replaced the 7310 and now it reads TOC and play some disc ok. Got ERR on some other discs but I'll leave that for later as I have another problem at hands.
I have no sound from either L or R channel. Dead quiet. I checked the relay circuit, all good. I monitor the output posts and inject a sound signal from another source at just after the DAC 1541 and Ive got sound coming out from at the posts so the opamp section is OK. This leaves me with the 1541, saa7220 and the saa7310 which Ive just replaced.
So I did a few more tests to isolate the problem. I got the eye pattern at the HF point so the laser is OK albeit not very clear. This line then goes to the decoder 7310 (pin 32) and out at pin 2. The waveform at pin 2 is not what expected, this waveform is the same as measured at the output posts.
Im I right in thinking either the 7310 or the 7220 is toasted? I'm leaning toward the 7310 because it is the decoder and the waveform measured at pin2 doesnt look like it is as it should. Ive already ordered another 7310 and a saa7220 so we will see which one is the culprit.
Any advice and suggestions are greatly appreciated.
HF
7310 pin2
output post
Replaced the 7310 and now it reads TOC and play some disc ok. Got ERR on some other discs but I'll leave that for later as I have another problem at hands.
I have no sound from either L or R channel. Dead quiet. I checked the relay circuit, all good. I monitor the output posts and inject a sound signal from another source at just after the DAC 1541 and Ive got sound coming out from at the posts so the opamp section is OK. This leaves me with the 1541, saa7220 and the saa7310 which Ive just replaced.
So I did a few more tests to isolate the problem. I got the eye pattern at the HF point so the laser is OK albeit not very clear. This line then goes to the decoder 7310 (pin 32) and out at pin 2. The waveform at pin 2 is not what expected, this waveform is the same as measured at the output posts.
Im I right in thinking either the 7310 or the 7220 is toasted? I'm leaning toward the 7310 because it is the decoder and the waveform measured at pin2 doesnt look like it is as it should. Ive already ordered another 7310 and a saa7220 so we will see which one is the culprit.
Any advice and suggestions are greatly appreciated.
HF
7310 pin2
output post
Last edited:
Dowser
Learning to bodge again..
Hi - go and review my CDI thread here too, I've had some fun and games with my 2 CDIs too. Mine were also fixed with new 7310s. However, messing around with PSU strategies I managed to kill one player two times further - no audio out, both times the SAA7220. No guarantee yours is - on mine I was able to use a scope and copmpare between working and non-working players...so quite easy...
Note: most cannot see your photos - you need to move them to a different hoster - I use Flickr.
Note: most cannot see your photos - you need to move them to a different hoster - I use Flickr.
Dowser
Learning to bodge again..
Yes, pin 2 isn't correct, but in my case it wasn't the 7310, but the 7220 that was pulling the signal down - I will see if I can grab 15 mins this evening to show you a working signal. I got replacement saa7220s from UTSource delivered within a week or 10 days, for not much more than cheapest on Aliexpress...and my Aliexpress order never arrived and had to be disputed 