Ah NJoe TJoeb 4000 CD player problem

[cod]

Hi there

I have owned one of these fine TUbe output CD players for about 4 years now, all was well up until this morning and i would be very appreciative of any insights you may have. I bought a CD, that i played this morning and i could only hear the right channel.

Now stupidly I took the cover off thinking it was the tubes, that one had gone. So i got an old pair of Philips tubes that come with the CD player, and tried them, still no luck!.

on the control board and im no expert at these things, but there are 2 Burr brown opamps, set parralel to one another, i thought one of those might be the problem. There was also another small chip of the same size i think is the DAC chip. I took them out reseated them, changed them round , (only the opamps).

Maybe stupidly the wrong way round, the opamps have 8 pins 1- 4 5 - 8 I turned them round only because I forgot which way they went round. I usually do a little diagram before undertaking such work, but alas i didnt, fool!. Well the thing is it was the bloody Cd that was at fault. Overjoyed when I played my Meddle Album, In perfect stereo, was really happy. But to my horror... now at low levels i get a distortion sound and a slight ghosting of a high pitch sine wave around the 6th octave of a piano.

It cuts out after certain low passages break into higher volume. but ambient music is awash with this distorted tone. I know the tubes all work, I know the fuse is good, Im just wondering if i have damaged the opamps, or the circuit board.

heaven help me if i have , i have to send it back to holland to be fixed if its not a straight replacement

so guys any insight would be much appreciated
Andy

[nightflier]

Short of reseating the tubes & opamps to check if there is a bad connection or something obstructing the contacts, it looks like this player is going back to The Netherlands. Maybe a local hi-fi shop will be willing to look at it?

[cod]

Actually most importantly, i erm changed the DAC chip the wrong way round also.

Dont suppose you could sabotage it more if you tried.

(Learning electronic, dos and donts very quickly)

I have actually got some replacement opamps, And it still sounded the same, so im now getting a replacement DAC. If not i will try my luck with someone locally. If i can find one, lots of Car hifi fitters and television maintenance come CD player fixers, but no specialists. We will see..

thanks for your comments

[Fergymunster]

Actually most importantly, i erm changed the DAC chip the wrong way round also.

Dont suppose you could sabotage it more if you tried.

(Learning electronic, dos and donts very quickly)

I have actually got some replacement opamps, And it still sounded the same, so im now getting a replacement DAC. If not i will try my luck with someone locally. If i can find one, lots of Car hifi fitters and television maintenance come CD player fixers, but no specialists. We will see..

thanks for your comments
Not you again Cod.Jesss,Save your piece of mind and get a replacement CD player and through your current one in the garbage can.

[cod]

Not you again Cod.Jesss,Save your piece of mind and get a replacement CD player and through your current one in the garbage can.


Naa its quality, and anyhow,Im off work serioulsy ill so getting no money. would love a newie, but, great news its got the DAC and is working like a dream again, *smiles*

[Fergymunster]

Naa its quality, and anyhow,Im off work serioulsy ill so getting no money. would love a newie, but, great news its got the DAC and is working like a dream again, *smiles*
I'd be "seriously ill" too if I had your had your problem.

[teridon]

hello! i think we got the same problem, getting single-channel distortions with the AH!

what do you think should be replaced, the entire output board or simply the DAC?

if at all, how much did you spent for that?

[hydroman]

Lillte too late - but for next time..

Take a picture before you start.

Only mess with one channel at a time - swapping at the highest stages (i.e. 'whole board' ) first to see if the problem moves. THEN get into component and sub component level....

Take your time to un-fark it. Good luck, mate!

[teridon]

hello!

i have finally isolated much of the parts of the ah njoe tjoeb that might be the source of the distorted left channel.

1. not the philips tubes - i switched the tubes and the distortion in the left channel remained.

2. not the goldplated RCA outputs- i tried putting bare-wire interconnects on the left channel, same distorted effect.

nonetheless, by doing this, i also conclusively discovered that the distortions by the left channel included only the low-frequency sounds and not the high-frequenecy ones, as the sound of bass drums absolutely distorted.


3. whether the DAC is the problem - im not quite sure as yet.

though what i can say is that when i use the headphone output of the ah njo tjoeb, there is absolutely no distortion. therefore, we can surmise that if there is no distortion in the headphone output and logically, the sound in the cans still pass through the DAC, maybe the DAC is not the problem.

4. whether the tube outputboard itself is the problem - MAYBE.

i tried checking for loose and lousy connections. disconnected the outputboard from the main unit, checked over and under. reconnected the opamps and the DAC.
but when i reattached the outputboard, same situation, same distorted low-frequencies of the left channel.

I did one fatal error though.
as i was reconnecting the components of the pcboard to the different cd player parts, one of the wires suddenly let off a spark. maybe because i messed up the connections from the output board to the transformer sections. therefore, the cd player at present is dead.

nonetheless, i have a few questions, in light of the facts i have stated above.
1. as my cd player is dead, do you think it is merely due to a blown fuse, therefore, replaceable by some generic repair shop?

2. if i do get my cd player alive again, what do you think about these next few steps ill take to finally rid the low-frequency distortions:

a. replace the DAC. however, if you think i made the right observations re the DAC-headphone output connection, there might be no problem with the DAC at all.

b. have the output board examined by a specialist repair shop

i was thinking, is it insanely possible for repair specialists to check the fuses and the bits and pieces in the outputboard itself, as maybe the connections or parts went wrong some way, some where.

more so, do you think this is a mere matter of faulty connectors, particularly from the outputboard wiring to the RCA outputs itself, or can this also be a matter of defective tube sockets?

c. as a final recourse, replace the outputboard.

if so, do you guys know how much this thing might cost and where it is sold?

thanks a lot!

[epz]

Hi teridon,
Did you solve the problem?
I have problem with mine ah tjoeb, disortion on high frequencies and left channel much to loud. I already chsnged capcitors c37 and c35, but still problem. I have the upsampler and no opamps.
Do you have suggestions for repair?
Paul