Its me again - my nakamichi drives me crazy! I simply won't get it running when its cold. It plays about a minute, then spins the disc up and down, partially reversing and the feed motor might even drive the pickup to the outer end without stopping. If I don't switch it of, it would destroy the drive (or one of the gearwheels - as happened before). As i only had distorted nf on the rca's , I soldered out the mute transistors - now, when the drive's gone crazy, it crackles and hisses.
I resoldered the whole digital section - no effect
I changed the ribbon from pickup to pcb - no effect
One thing is strange. When I touch the ribbon cn-102 (link to schematics below - it connects the detector diodes with cxa1081) with my fingers, me being not earthed, the player starts going crazy. He doesn't do it when I use some isolating material to touch it or when I touch the case with my other hand. This very much seems like a grounding prob of the pickup, but can that be??? Is the detector circuit always that sensitive? Any capacitors fault?
Once the player got crazy, i have to switch it off for hours or to unplug the mains for some seconds. Even if i take out the disc, the player buzzes, crackles and hisses...
Any help??? I start running out of ideas! Unfortunately i've got no oscilloscope...
schematics: http://tinyurl.com/4rlht
matthias...berlin...germany
I resoldered the whole digital section - no effect
I changed the ribbon from pickup to pcb - no effect
One thing is strange. When I touch the ribbon cn-102 (link to schematics below - it connects the detector diodes with cxa1081) with my fingers, me being not earthed, the player starts going crazy. He doesn't do it when I use some isolating material to touch it or when I touch the case with my other hand. This very much seems like a grounding prob of the pickup, but can that be??? Is the detector circuit always that sensitive? Any capacitors fault?
Once the player got crazy, i have to switch it off for hours or to unplug the mains for some seconds. Even if i take out the disc, the player buzzes, crackles and hisses...
Any help??? I start running out of ideas! Unfortunately i've got no oscilloscope...
schematics: http://tinyurl.com/4rlht
matthias...berlin...germany
A wild guess 😉
Check the state of C202 (1000µF/35V-)
if wornout it could drag the -5V and -9V supply down
Check the state of C202 (1000µF/35V-)
if wornout it could drag the -5V and -9V supply down
Thanks!
Hmm, C202 only gets about handwarm, just as C204 and the big psu caps 3300/25. Its glued to the pcb, so I cannot see whether its a ran-out cap.
I checked out the -5/-9Volts on some points and have them in a variation of .1/.2volts, but the point given at D120 (-32V dc) has only -28.5 to -29volts and around the zener zd102 i have -21 instead of -22.5 and -27 instead of -28.8.
Might that be a sign c202 and /or c204 are weak? They're not costy, so I could change them anyway.
matthias
Hmm, C202 only gets about handwarm, just as C204 and the big psu caps 3300/25. Its glued to the pcb, so I cannot see whether its a ran-out cap.
I checked out the -5/-9Volts on some points and have them in a variation of .1/.2volts, but the point given at D120 (-32V dc) has only -28.5 to -29volts and around the zener zd102 i have -21 instead of -22.5 and -27 instead of -28.8.
Might that be a sign c202 and /or c204 are weak? They're not costy, so I could change them anyway.
matthias
short update:
changed both c202 and c204 for new ones rated 1000/35/105°c. Works better, but still not stable in cold condition (my room 17°c), so next week i'll change all the psu electrolytes assuming they (all: taicon 85°c) are past their best days.
The voltage drop to values given in the manual was obviously caused by measuring in operation. They're still about the same now.
changed both c202 and c204 for new ones rated 1000/35/105°c. Works better, but still not stable in cold condition (my room 17°c), so next week i'll change all the psu electrolytes assuming they (all: taicon 85°c) are past their best days.
The voltage drop to values given in the manual was obviously caused by measuring in operation. They're still about the same now.
Hi Hiwiho,
Unfortunately your CD player has a provision for a full tracking and servo adjustments. You'll need an oscilloscope!
Start at pin 2 of U101 and check the waveform, it should be 1.5V p-p while CD is playing (any music CD will do fine). If this checks okay, proceed with focus and tracking adjustments. you'll need a test CD (Technics for example). Instructions usually come with the test CD.
Unfortunately your CD player has a provision for a full tracking and servo adjustments. You'll need an oscilloscope!
Start at pin 2 of U101 and check the waveform, it should be 1.5V p-p while CD is playing (any music CD will do fine). If this checks okay, proceed with focus and tracking adjustments. you'll need a test CD (Technics for example). Instructions usually come with the test CD.
update2:
Today was the first time in the last 3 days it went crazy again. Being switched off since yesterday, the mains plug remained plugged, and perhaps 40seconds after start the disc remained rotating, but the signal got lost completly...the player sounding like searching a station on an analogue am tuner: grizzling, sweeping.
But unlike before, i could stop both noise and disc with the stop-button. A reload of the disc meant no spinup. Unplugged the mains for some seconds and now it's playing erversince.
@ extreme_boky: Yes, the player offers full adjustment resistors, but the manual says I need a special switchbox (schematic included in service manual) thats plugged to a multipin-serviceconnector in combination with frequency counter, 2channel-osc and signal generator. I lack all of these 🙁 could just get my hands on a 1channel-version...
And I don't really think its the pickup. When it runs, I've got no clicks, no skipping and fast tracking even on poor cdr.
I ordered replacement electrolytes for all taicons in the ps and hope it's done when finally changed. At least Pmiks guess meant some 80% improvement on the naka. Thanks for that. I knew danes never lie
matthias
Today was the first time in the last 3 days it went crazy again. Being switched off since yesterday, the mains plug remained plugged, and perhaps 40seconds after start the disc remained rotating, but the signal got lost completly...the player sounding like searching a station on an analogue am tuner: grizzling, sweeping.
But unlike before, i could stop both noise and disc with the stop-button. A reload of the disc meant no spinup. Unplugged the mains for some seconds and now it's playing erversince.
@ extreme_boky: Yes, the player offers full adjustment resistors, but the manual says I need a special switchbox (schematic included in service manual) thats plugged to a multipin-serviceconnector in combination with frequency counter, 2channel-osc and signal generator. I lack all of these 🙁 could just get my hands on a 1channel-version...
And I don't really think its the pickup. When it runs, I've got no clicks, no skipping and fast tracking even on poor cdr.
I ordered replacement electrolytes for all taicons in the ps and hope it's done when finally changed. At least Pmiks guess meant some 80% improvement on the naka. Thanks for that. I knew danes never lie
matthias
np!
European (skilled) engineers havnt used this cheap trick in four decades and why not?
A leason was learned and wrote down in the black book of what not to do......it simply fails to fast 😉
Its just the fact that C202 is under great stress, when used in this fashion to gain double voltage
European (skilled) engineers havnt used this cheap trick in four decades and why not?
A leason was learned and wrote down in the black book of what not to do......it simply fails to fast 😉
Its just the fact that C202 is under great stress, when used in this fashion to gain double voltage
I am not a big fan of voltage doubler topologies either half wave or fullwave, but just about every computer on the planet that operates on 100V - 120V with a switching supply uses one. (fullwave) Like anything else it is a matter of picking the appropriate component for the job - I have a now retired pc that ran continuosly for about 8 years and that switcher still works fine...
Without knowing the ac line voltage the voltages measured on C202/C204 are not conclusive. Generally there is also a tolerance on the values given by the manufacturer, and distortion of the ac mains waveform may also slightly affect the value.
Without knowing the ac line voltage the voltages measured on C202/C204 are not conclusive. Generally there is also a tolerance on the values given by the manufacturer, and distortion of the ac mains waveform may also slightly affect the value.
115 Volt line rectifired/doubled for 2x 250V- electrolytic-caps. should give a nice stabile lifespan 😉
The C202 in the "Naka" goes very thight at the rated cap. voltage
The C202 in the "Naka" goes very thight at the rated cap. voltage
Well, i can change c202 from time to time 😀 It's only for the display anyway (which is bright and clear)
btw: The affected voltages (-5/-9volts) are for the analogue section, i saw today with a look to the block diagram...
Today when i wanted to warm the player up before playing, it started sweeping and grizzling on the rca out even without playing (but a disc was inside - in stop mode) about half a minute after being switched on. A minute later, it worked perfect again...
Tomorrow i'm gonna switch it on with cn102 detached. See if it still gets crazy with the detector diodes missing.
matthias
btw: The affected voltages (-5/-9volts) are for the analogue section, i saw today with a look to the block diagram...
Today when i wanted to warm the player up before playing, it started sweeping and grizzling on the rca out even without playing (but a disc was inside - in stop mode) about half a minute after being switched on. A minute later, it worked perfect again...
Tomorrow i'm gonna switch it on with cn102 detached. See if it still gets crazy with the detector diodes missing.
matthias
(B) Voltage not even close at the drive (duh!) 😉
looked sole on which components stressed most...if one cap located far away from the prob course better work condition in generel.........then you need to refurbish this unit quite a lot regarding E-Caps, that if you want it in a perfect state.
Quote:
partially reversing and the feed motor might even drive the pickup to the outer end without stopping.
Since the Feed and discmotor is powered by +11(A) and -11(B) i dont know which one disconnected whould give the qouted respons...
Have you had the fuses TF101 and TF102 checked if they are good and seated probely??? 😕
If they combined with R204/205 are aproved not to give probs ...
Then next check out the function of:
'U113
U114
C176
C177
C178
C179
It seems like a PSU related problem....mostlikely coursed by one of the suggested components 😉
looked sole on which components stressed most...if one cap located far away from the prob course better work condition in generel.........then you need to refurbish this unit quite a lot regarding E-Caps, that if you want it in a perfect state.
Quote:
partially reversing and the feed motor might even drive the pickup to the outer end without stopping.
Since the Feed and discmotor is powered by +11(A) and -11(B) i dont know which one disconnected whould give the qouted respons...
Have you had the fuses TF101 and TF102 checked if they are good and seated probely??? 😕
If they combined with R204/205 are aproved not to give probs ...
Then next check out the function of:
'U113
U114
C176
C177
C178
C179
It seems like a PSU related problem....mostlikely coursed by one of the suggested components 😉
Today the player even played crazy with the detector diodes detached. ... giving his high broadband noise as ever which then gets more low-frequent and suddenly stops. Normally the player works normally then. If happening tomorrow, I will tape it.
I changed the ceramic on the transformer pcb, U114, C190/191 , C205/206 today (the elcaps will arrive later from reichelt). U113 is mounted on a hetasink thats soldered to the pcb. As the pcb is of the worst quality I've ever seen (decomposes if soldered on more than 2secs - already had to wire some pins on the opamp I changed) I will not change it. It gets nicely warm and I could easily test to warm upthe heatsink before starting operation. The player works at the moment. I'm curious on tomorrow morning
TF101 and 102 are uncheckable for me. Theyre mounted together with the resistors in separate shrunk-hose. The part list says they're "thermal fuse 126" which leaves me clueless. After all, I'm a geographer. I know how to use a dmm, can make photoplated pcbs and solder together almost everything but that's it somehow.
By the way: Is there any interest in the whole manual of the naka as pdf? As some sort of giving back something for your efforts I could offer that at least...
matthias
I changed the ceramic on the transformer pcb, U114, C190/191 , C205/206 today (the elcaps will arrive later from reichelt). U113 is mounted on a hetasink thats soldered to the pcb. As the pcb is of the worst quality I've ever seen (decomposes if soldered on more than 2secs - already had to wire some pins on the opamp I changed) I will not change it. It gets nicely warm and I could easily test to warm upthe heatsink before starting operation. The player works at the moment. I'm curious on tomorrow morning
TF101 and 102 are uncheckable for me. Theyre mounted together with the resistors in separate shrunk-hose. The part list says they're "thermal fuse 126" which leaves me clueless. After all, I'm a geographer. I know how to use a dmm, can make photoplated pcbs and solder together almost everything but that's it somehow.
By the way: Is there any interest in the whole manual of the naka as pdf? As some sort of giving back something for your efforts I could offer that at least...
matthias
Just when I had connected it to my pc, it did behave normally... but the error's not gone. Guess i will make a living with it... if....if...there wasn't something wrong with the player in general. As an explanation: I bought it very cheap from german ebay for only 12euros ("defect: failing from time to time") as replacement for my marantz63 which totally died. I thought, I would replace laser unit in the naka and that'll do.
By now, I've:
Changed a worn gearwheel in the drive
changed cable cn102
replaced some psu caps (C191/191/205/206/202/203/204)
replaced a zener (zd101)
soldered out mute transistors (q122/123/132/133)
replaced opamp u112 (njm5332) for a op275
resoldered the whole digital section
Ok, it plays when warm, but sounds rather horrible. Cold, harsh highs, undynamic mids. Ok, its a lot like the old esprit-sonys, but I expected a nakamichi at least to play better than my discman. So I checked it once again with the help of my pc soundcard and adjusted the distortion potis of the ad1864n. Sound stayed the same. I burned some test signals onto cd and got surprised:
applying a fast sine sweep from 20hz to 20khz led to cracks and clicks from the higher mids on - both on the digital out as on the analog out. The drive was rather irritated by the track and had a longer seek time than usual. Single sines are played well except sometimes highs when louder than around -10dB. But the main point was, when I played white noise at -6dB. the amplitude changed between -3dB and around -7db every ~0.3 of a second (link: upper graph original, below from my naka). However, this doesn't happen with sine waves. Some sort of digital signal misbehaviour.
Any idea where this comes from? I had some probs with the mute section (thats why i soldered the trans out), but the pins on dsp and servo proz get low/high as they should. So I don't thinks it's a mute signal irritating the dsp.
Any advice? Otherwise i'll dispose that thing off..., grab my last euros and buy myself a new denon 685/1450 or a nad 521bee
By now, I've:
Changed a worn gearwheel in the drive
changed cable cn102
replaced some psu caps (C191/191/205/206/202/203/204)
replaced a zener (zd101)
soldered out mute transistors (q122/123/132/133)
replaced opamp u112 (njm5332) for a op275
resoldered the whole digital section
Ok, it plays when warm, but sounds rather horrible. Cold, harsh highs, undynamic mids. Ok, its a lot like the old esprit-sonys, but I expected a nakamichi at least to play better than my discman. So I checked it once again with the help of my pc soundcard and adjusted the distortion potis of the ad1864n. Sound stayed the same. I burned some test signals onto cd and got surprised:
applying a fast sine sweep from 20hz to 20khz led to cracks and clicks from the higher mids on - both on the digital out as on the analog out. The drive was rather irritated by the track and had a longer seek time than usual. Single sines are played well except sometimes highs when louder than around -10dB. But the main point was, when I played white noise at -6dB. the amplitude changed between -3dB and around -7db every ~0.3 of a second (link: upper graph original, below from my naka). However, this doesn't happen with sine waves. Some sort of digital signal misbehaviour.
Any idea where this comes from? I had some probs with the mute section (thats why i soldered the trans out), but the pins on dsp and servo proz get low/high as they should. So I don't thinks it's a mute signal irritating the dsp.
Any advice? Otherwise i'll dispose that thing off..., grab my last euros and buy myself a new denon 685/1450 or a nad 521bee
Attachments
When doing warming to selected ics of the naka, I found out cxa1081s is only working properly when warm. If not, the laser won't try to focus (but dimms red), when getting warm the disc starts to spin and the output crackles (reading without having focussed). When warm, it focusses and plays.
cxa1081s ... anyone knows where I could get a spare??
I found a list on:
http://www.divdev.fsnet.co.uk/icxref2.htm
saying that:
cxa1081 Kenwood DP-M109
cxa1081 Pioneer XR-P500
cxa1081 Sony CDP 222ESD
cxa1081 Sony CDP-C500
cxa1081 Sony CDP-C5M
cxa1081 Sony CDP-CX100
cxa1081 Sony CDP-M48
these players contain the ic. Is there another replacement possible for it?? I found no manual, only the schematic, which you can download here (250k):
www.listmember.de/diyaudio/cxa1081s.gif
cxa1081s ... anyone knows where I could get a spare??
I found a list on:
http://www.divdev.fsnet.co.uk/icxref2.htm
saying that:
cxa1081 Kenwood DP-M109
cxa1081 Pioneer XR-P500
cxa1081 Sony CDP 222ESD
cxa1081 Sony CDP-C500
cxa1081 Sony CDP-C5M
cxa1081 Sony CDP-CX100
cxa1081 Sony CDP-M48
these players contain the ic. Is there another replacement possible for it?? I found no manual, only the schematic, which you can download here (250k):
www.listmember.de/diyaudio/cxa1081s.gif
Strange problem......and you are sure it is not VR101,VR102,VR103 which twisted by higher temperature and by this gets better contact ???
German supplier of the CXA 1081S
http://www.donberg.ie/descript/c/cxa1081s.htm
German supplier of the CXA 1081S
http://www.donberg.ie/descript/c/cxa1081s.htm
Hi PMik,
no, it's not the potis. I turned them a bit left right with the position marked before. it was the first thing I did in general. I warmed cxa1081 with my finger on the housing of the dip before turning the naka on. Disc rotated, crackling. Let it cool down again, turned it on... nothing. Then i put something warmer than my finger on the cold dip to warm up more than my finger could. turned it on... working. So it can't be a therm-prob of the laser unit, too.
Why I had the idea to check that? Yesterday I checked all voltages given in the schematic and they were ok. Only the voltages around q101 were wrong as I had +5Volts, +4.3 decreasing to 3.6 during 5secs measuring and 1.3volts decreasing to around .7volts. So I will change q101 and c101 as well.
Heating up this portion of the pcb with a dryer means perfect playing - I had carefully resoldered this whole part of the pcb a week ago, so it can't be a cold pin.
btw: Couldn't hesitate to keep on searching even after I had posted and found a spare. It's listed in the euras-system and I ordered it for 4euros plus 6euros shipping as an "original onkyo spare cxa 1081s". Could have payed 50euros as well. I dont know if it's dip or some other shape. I will heat up my acid, if neccessary to make a carrier pcb...
Doenberg would have also been possible (thanks for the link!) but they're from ireland so more shipping...
Have a nice evening,
matthias
no, it's not the potis. I turned them a bit left right with the position marked before. it was the first thing I did in general. I warmed cxa1081 with my finger on the housing of the dip before turning the naka on. Disc rotated, crackling. Let it cool down again, turned it on... nothing. Then i put something warmer than my finger on the cold dip to warm up more than my finger could. turned it on... working. So it can't be a therm-prob of the laser unit, too.
Why I had the idea to check that? Yesterday I checked all voltages given in the schematic and they were ok. Only the voltages around q101 were wrong as I had +5Volts, +4.3 decreasing to 3.6 during 5secs measuring and 1.3volts decreasing to around .7volts. So I will change q101 and c101 as well.
Heating up this portion of the pcb with a dryer means perfect playing - I had carefully resoldered this whole part of the pcb a week ago, so it can't be a cold pin.
btw: Couldn't hesitate to keep on searching even after I had posted and found a spare. It's listed in the euras-system and I ordered it for 4euros plus 6euros shipping as an "original onkyo spare cxa 1081s". Could have payed 50euros as well. I dont know if it's dip or some other shape. I will heat up my acid, if neccessary to make a carrier pcb...
Doenberg would have also been possible (thanks for the link!) but they're from ireland so more shipping...
Have a nice evening,
matthias
hi hiwiho,
i got a cdp337esd with a similar problem you had. Fortunately I also have an oscilloscope.
My case is this: no cd spinned after power on, i can only noticed the red beam from the laser unit. I had tried to adjust VRs but no improvement. Do you think it's the CXA1081 problem?
The voltage at the collector of Q101 should decrease because of C101 (for me is C102 100microfarad 10v), perhaps, the voltage at the base should be fixed, i had a 4.6v. Besides, i found a around +4v on pin8 while it should be measured 0v...
Did you get the spare part? Do you solve the problem? thank you.
i got a cdp337esd with a similar problem you had. Fortunately I also have an oscilloscope.
My case is this: no cd spinned after power on, i can only noticed the red beam from the laser unit. I had tried to adjust VRs but no improvement. Do you think it's the CXA1081 problem?
The voltage at the collector of Q101 should decrease because of C101 (for me is C102 100microfarad 10v), perhaps, the voltage at the base should be fixed, i had a 4.6v. Besides, i found a around +4v on pin8 while it should be measured 0v...
Did you get the spare part? Do you solve the problem? thank you.
Wow, after 3 years ;-)
Hey... you can find the CXA1081S at www.segor.de , a very reliable small dealer in berlin. They still have it, it's 4.40eur.
I don't remember exactly, but i don't think i changed it in 2004. I found the whole circuitry of the nakamichi to be very sensitive to any metal or conductive stuff nearby, so i gave up measurements at some point. I replaced the Laser and with patience, i found an adjustment (without measurements) where it worked. It still does, by the way, but i don't use it very often. But still, if for instance i touch one of the (insulated!!) cables from the pcb to the pickup, the servo circuit goes mad.
Matthias
Hey... you can find the CXA1081S at www.segor.de , a very reliable small dealer in berlin. They still have it, it's 4.40eur.
I don't remember exactly, but i don't think i changed it in 2004. I found the whole circuitry of the nakamichi to be very sensitive to any metal or conductive stuff nearby, so i gave up measurements at some point. I replaced the Laser and with patience, i found an adjustment (without measurements) where it worked. It still does, by the way, but i don't use it very often. But still, if for instance i touch one of the (insulated!!) cables from the pcb to the pickup, the servo circuit goes mad.
Matthias
- Status
- Not open for further replies.