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Nakamichi 580 no audio at RCAs & headphone jack

Why didn't you order from Digikey. They are only $0.76 each and in stock by Texas Instruments, they are the real ones. Yes, you need to pay $5 for shipping, but you order 10 each they are $0.54 each. The CD4011BE is also $0.76 or $0.54 each when you order 10. When you order from Amazon you don't know where it's coming from.
(no affiliation with Digikey)
Digikey
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dankik said:
Why didn't you order from Digikey. They are only $0.76 each and in stock by Texas Instruments, they are the real ones.
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1) Yeah, exactly! And, as noted previously, that's the EXACT same TI CD4001BE ordered previously from DigiKey that killed the 4011! So I might as well possibly try something different (or not...).

2) I'm impatient. I'm getting very tired of messing with the 580. The DigiKey orders take much longer to arrive, then they are often further delayed by USPS. By the time I pay the shipping I can get 20 ICs from Amazon for the price of 2 from DigiKey. Not that I need more... The Amazon order arrives tomorrow without USPS issues.
 
When I worked in the electronics industry, we always needed to verify that the parts we installed were genuine so we didn't buy from non-traceable sources.
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dankik said:
When I worked in the electronics industry, we always needed to verify that the parts we installed were genuine so we didn't buy from non-traceable sources.
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Agreed that traceability is desirable. But it's a tape deck. It's not an aerospace or mil spec application. ;)

Either they work or they don't. Amazon, unlike DigiKey, has free returns with same day refund if they don't. :)

(Of course, knowing my luck, the whole deck will get trashed from a defective IC after saying this!)
 
FF & REW are now impossibly slow. They're both maybe only 3x or so faster than play! A 90 min. tape took nearly 5 minutes to FF to end! :(
 
gnexus said:
FF & REW are now impossibly slow. They're both maybe only 3x or so faster than play! A 90 min. tape took nearly 5 minutes to FF to end! :(
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Now I get it!
The damn thing is stuck in PAUSE because of the bad IC404(CD4001). So it thinks it's in CUE mode. That causes REW & FF to run at 1/3 normal speed.
 
Just got the CD4001 & CD4011 from Amazon. The 4001s are TI. The 4011s are not...

Replaced IC404 (again...). This time it still works and didn't fry any adjacent ICs. So must assume that either the one from DigiKey was defective or that my definitely non-compliant ESD procedures killed it (probably more likely!).

Unfortunately no change after replacing IC404. Still works the same= everything works, including pause, but the pause light is on. So must also assume the deck still thinks it's in pause. That means it's probably still in mute and 1/3 speed FF & REW also. Haven't checked that yet because most likely fixing the pause lamp will also fix those issues if still present.

Edit: yes it's in pause. Rew & FF still 1/3. Mute is also still on. That should mean it's logic and not afterwards.

Something else apparently got killed by either the solder debris or the bad ICs.

But it's an improvement over what it was because now pause output works at IC404(4). Big question now is what else got trashed?
 
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They are CMOS chips so you should be wearing a wrist strap and working on an anti-static mat to prevent damage.
 
dankik said:
They are CMOS chips so you should be wearing a wrist strap and working on an anti-static mat to prevent damage.
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No doubt! ;)

Of course I know better than to do CMOS work without any ESD safeguards! I've been through extensive ESD training countless times. But currently have nothing of the sort at my makeshift workbench. Not even a wrist strap. That's even though I'm working on computer hardware here all day.

Everything like that, such as oscilloscopes, other test equipment, ESD mat, power screwdrivers and such was either destroyed in the flood or perpetually on a "todo" list... :(
 
Man! This pause thing was really kicking my butt!
Thought I would NEVER find it! The light stayed on no matter what! Even after replacing the two ICs and the transistor sinking the lamp voltage it STILL stayed on. Even after removing the resistors it STILL stayed on! Mind boggling! :(

But it turned out it wasn't even the solder debris that caused the problem! Instead it was two wires on the control panel that got pinched together when I was replacing the stop lamp and other bulbs. It was okay at first. But then after moving the deck repeatedly for testing it seems the wires finally shorted. :(

Crazy stuff! And another careless mistake! :(
The solder crap was bad enough. I can't believe that happened. I'm usually more detailed than that. I'm getting careless with this thing, just like with the ESD. I usually take better ESD precautions even without proper equipment. Guess I'm getting too fed up and worn out with this deck. It's been too long! Many months of troubleshooting and repairs...

So now need to cut & splice two wires. Then hopefully it'll work again...

The major reason for this problem was the way these very early old 580s were made. They're basically hand built. Even the PCB components are inserted by hand! They're not machine made like the 480s and later decks. The wiring is also done by hand. So when you start messing with things and doing necessary things like cutting wire ties it's very easy to not get them back into the same position. Then wires can easily get pinched or abraded.
 
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FF and REW now back full speed! :)

But it's still in mute... Pause lamp still also on. But it's very dim. So making progress. But a transistor is still leaking current somewhere. Not surprising after a big short like that! :(
 
Still can't locate the remaining issue with dim pause light... :( Edit: The problem is definitely that Q413 isn't fully turning off.

IC404 was actually okay! So reinstalled the original.
Q413 is also good. Replaced multiple times.

Removed PCB jumper from pin12 to mute circuit. That got the deck out of mute without disconnecting the wire to main PCB pin 25. It also eliminates the possibility of any leakage from the mute circuit causing the pause lamp to be on.

So for some reason Q413 isn't fully shutting off and has leakage current. But it's been replaced with several different new ones with no change. R452 has correct resistance. 6V at lamp (pin12). 630mV at Q413 (b). 4mV at IC404(4).

Don't get it! Do I have countless leaking 945 transistors? How can I get Q413 to fully shut off?
 
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Gave up on the pause lamp issue for now. :(

So tried a recording test:

Calibrated record level to 0dB using tuner 330Hz tone. No faint noise on playback. So either it's gone now or there's an issue with the built-in 400Hz tone.

Then tried to record music from tuner. Recording sounds great now! :)

So this deck would be about done if can fix the pause lamp issue.
 
Swapped Q413 with one from FF lamp. Now pause lamp is off and FF lamp is dimly on. That proves the 945 transistor is leaking. But that also means all the other 945s I currently have, both new & used, are also leaking even though they work fine for other applications.

Anyway, that allowed the jumper to the mute circuit to be reinstalled. :)
 
Tried another 945 from Amazon (because free shipping &returns) . Didn't work either. This one gives extremely dim FF lamp in stop mode and NO lamp in FF.

I don't have a transistor tester that could show specs of the other working original 945s. Obviously they're different from the original 945s in the audio circuits and remote. But they have EXACT same markings?

Does anyone know how to get a correct 945 transistor?
 
I just noticed this post on your other thread. I think he means 2SC945.
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Datasheet for 2SC945 is above. Pinout = ECB
Datasheet for KSC945 is here. Pinout = EBC
You want to order KSC945C (center collector)
Pins reversed.
You probably bought KSC945??
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dankik said:
The datasheet shows different gains depending on the suffix. Are all of yours the same?
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The ones that work are original Nakamichi (no mfr on transistor) from adjacent button lamps. They are marked 945(L). The 580 manual parts list shows only 2SC945.

The ones tried so far: [RESULT]
1) 945(L) from Nak RM-580 remote [FF lamp on in stop]
Tried several of those... work fine elsewhere
2) Generic 945 from Amazon [FF lamp on in stop]
Tried two of those... work fine elsewhere
3) Second Amazon 945 batch [lamp very dim in stop and off in FF]. Test batch that's getting returned to AMZ.

Haven't yet tried others as 945 is not stocked by DigiKey. There are alternatives to 945. But have no clue what to get since I don't know the needed specs and it's very sensitive to variation. Thought of changing or adding resistance?

No KSC945s have been ordered or tried! ;)

Just noticed that there's 20 945s used on the logic PCB. So I can possibly steal one from the logic circuits to use. Then hopefully can replace it with a 945(L) in a spot that's less sensitive to variation.
 
This is absolutely nuts!
Even 945s from same lot number still light up!
They're using only P17Y lot for lamps and other lots for other 945s. So I tried using both Q425 and Q422, which were both P17Y. Neither worked!

Only remaining option I see is adding resistance on control PCB to FF lamp.
 
Can't tell anymore if it's a replacement lamp. But maybe that has something to do with the issue. But originally it was the pause lamp.

A 1k resistor gets the light out... permanently... :(

Any ideas on the value of a resistor that will kill the dim light in stop, but keep it on at decent brightness in FF?

Actually looks like the original lamp. Maybe could swap lamps. But would probably just change the location - same as the transistors...

This is nuts! Never thought I'd be spending hours on a single light bulb! :(
 
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