Author Topic: Marantz PMD430 portable cassette recorder - No Audio  (Read 3488 times)

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Offline Bargainhunter

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Marantz PMD430 portable cassette recorder - No Audio
« on: August 05, 2022, 07:26:37 pm »
I am having trouble with my Marantz.  I have no output with the Line IN, Line Out, Microphones or tape playback.  I do have the 4.5 volts and the 15 volts.  I do get a mum from the internal speaker when I probe the playback volume control so I know the output amp is working.  I am thinking the trouble may be in the muting circuit.  I have attached the schematic.  Since the sound affects both channels, it must be in a shared circuit.

Any help would be greatly appreciated.
[attach=1][attachimg=1]
 

Offline floobydust

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Re: Marantz PMD430 portable cassette recorder - No Audio
« Reply #1 on: August 05, 2022, 08:02:57 pm »
What do the VU meters, LED's do? In either Rec or Play.
 

Offline Bargainhunter

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Re: Marantz PMD430 portable cassette recorder - No Audio
« Reply #2 on: August 05, 2022, 09:46:14 pm »
The meters do not respond in playback or record.  The Rec LED lights on record but the peak LED does not light up even though I had the record level high.
The meter does indicate battery level when the button is pushed.  The Left meter does show a slight movement if I inject a tone at the volume control terminal.
I tried a microphone in the left and right mic inputs with no response.
 
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Offline floobydust

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Re: Marantz PMD430 portable cassette recorder - No Audio
« Reply #3 on: August 06, 2022, 04:25:01 am »
I first spend a minute or two look for fractured soldering joints, really common in portable gear.
With so much not working, there are a few mute buses to check and it's a bit complicated.
For playback it mutes on either STOP (QU03), FF/REW (QU04), PAUSE (QU02). The VU meters are also muted in STOP. Shorted capacitor CU02 2.2uF/50V at QU03 would leave muting stuck activated as if in STOP mode. Measure the three voltages on QU03 to see if it's on, causing the problem. QU03 collector goes high to activate muting. Or at connector JK02 to see the muting signals there from the PLAY, PAUSE, FF/REW switches.
The mute switches are DTC124 SOT-23 NPN digital transistor with built in resistors.
 

Offline David_AVD

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Re: Marantz PMD430 portable cassette recorder - No Audio
« Reply #4 on: August 06, 2022, 06:06:42 am »
For old cassette player with a mechanical operated record function, always clean the record / play switch as they get dirty and oxidised with age and can cause no audio issues. Look for the long skinny switch that has a lever / wire from the record button.
 

Offline Bargainhunter

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Re: Marantz PMD430 portable cassette recorder - No Audio
« Reply #5 on: August 06, 2022, 03:25:08 pm »
Thank you for your help.
I will try your suggestions
In the meantime, I injected a signal into the L&R line inputs with the unit in record mode.  I traced the signal to the P601 board.  Nothing after the P601 board.
I can't find a datasheet on the HA12048 which is a Dolby IC.  I think the problem must be a shared component affecting the voltages since I don't have any signal on the line out jacks, microphone inputs or the tape head playback.

I will check the components that were suggested.
 

Offline fzabkar

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Re: Marantz PMD430 portable cassette recorder - No Audio
« Reply #6 on: August 06, 2022, 07:50:05 pm »
FWIW, there is a block diagram for the HA12046 and HA12047 Dolby ICs on page 7 of the following service manual:

http://www.saabclarion.se/manuals/SaabClarion_86_ServiceManual.pdf

These ICs have the same pin count as the HA12048 ...
« Last Edit: August 06, 2022, 08:26:48 pm by fzabkar »
 

Offline floobydust

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Re: Marantz PMD430 portable cassette recorder - No Audio
« Reply #7 on: August 06, 2022, 08:30:05 pm »
Can you measure the voltages at the P601 Dolby board connectors JK06, JK06. The +3.3V rail is alive? It's from QU01 and runs many IC's.
I see it has a pesky DIN jack switch, it overrides the RCA jacks. Make sure that it is OK, as they never really get moved.
 

Offline Bargainhunter

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Re: Marantz PMD430 portable cassette recorder - No Audio
« Reply #8 on: August 09, 2022, 09:29:11 pm »
I found capacitor CL52 had a bulge at the top so I replaced it.  I have ordered some other "suspicious" looking caps.  I noticed on the schematic that CL52 (2200uf 16v) is in parallel with CL51 (2200uf 10v).  I'm thinking they did this because of space limitations but why is one 10v and the other 16v?  Maybe space limitations again.  I will check the voltages suggested once I install the replacement capacitors.

Thank you for your suggestions.  I believe I'm on the right track.

 

Offline Bargainhunter

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Re: Marantz PMD430 portable cassette recorder - No Audio
« Reply #9 on: August 12, 2022, 04:44:51 pm »
Here is the voltages I measured in play.
At QU03 :  B 14.9v  E 14.5v  C 0v .  I found the resistor RU03 which should be 220K was measuring in the megohms.  Another 220K R712 also measured in the megohms. Other 220K resistors measured okay.

Also at JK02 the voltages in play measured as follows:
Pin 1     0V
Pin 2     4.6V
Pin 3    14.5V
Pin 4    0V
Pin 5    4.5V
Pin 6    14.6V
Pin 7    13.9V
Pin 8    12.8V
Pin 9    9.5V

Let me know what you think.  Thank you.
 

Offline floobydust

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Re: Marantz PMD430 portable cassette recorder - No Audio
« Reply #10 on: August 12, 2022, 05:35:05 pm »
You can tell if a muting (logic) switch is turned on by the collector voltage at any of QU02, QU03, QU04. These are best to look at to see which if any of the 3 muting circuits are being turned on. You got 0V at QU03-C (stop muting) so it is off, good.
JK02 pin 9, pause muting for QU02, looks low at 9.5V maybe check RU06 or QU02 is leaky. QU02-C should be around 0V when it is not muting for the pause button.
 

Offline Smoky

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Re: Marantz PMD430 portable cassette recorder - No Audio
« Reply #11 on: August 14, 2022, 02:34:58 am »
A few years ago a bunch of used stereo gear was dumped in my lap. Two of these cassette decks were in the pile. One was apart so I stuffed all of its guts back inside and taped it up. Must have been a project at one time to get one of the two working since several service manuals and schematics came with them!






 

Offline floobydust

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Re: Marantz PMD430 portable cassette recorder - No Audio
« Reply #12 on: August 15, 2022, 04:10:07 am »
I think it was for making bootleg tapes lol. List price 1986 was $599, it's got Dolby-B and dbx compander, three-head.
Your Rev. 2 service manual might be worth scanning.
 

Offline Smoky

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Re: Marantz PMD430 portable cassette recorder - No Audio
« Reply #13 on: August 15, 2022, 04:06:45 pm »
There appears to be three versions of the schematics for this tape recorder. The original copy that the OP has posted is from 1984, the revision is dated 1992, and the 2nd edition is dated 1996.

Maybe the OP can post what the serial number is of his machine to see of it's after the serial number printed on the cover of the 2nd edition?

If I can figure out which of the two tape decks that I have is in the best of shape, I'd be willing to part-out the other if you guys need some :-+


 

Offline Bargainhunter

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Re: Marantz PMD430 portable cassette recorder - No Audio
« Reply #14 on: August 15, 2022, 08:37:12 pm »
Would you be willing to scan
the revised service manuals?
 

Offline David_AVD

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Re: Marantz PMD430 portable cassette recorder - No Audio
« Reply #15 on: August 15, 2022, 09:39:58 pm »
If you do scan any audio manuals, please consider uploading them to HiFi Engine. It's a great resource.
 

Offline Bargainhunter

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Update on Marantz PMD430 portable cassette recorder - No Audio
« Reply #16 on: August 18, 2022, 12:58:15 am »
I replaced sever 220K resistors that were reading very high.  I tested QU01, QU02 QU03 and QU04 in circuit using a curve tracer and they look okay.
I still get no sound and now I don't get any hum when I probe around the volume control.  Here are the voltages I took.
At the collector of QU01 - 4.5V
At the collector of QU02 - 14V
At the collector of QU03 - 10V
At the collector of QU04 - 0V
At the pins of jack JK02:
pin 1 - 0V
pin 2 - 4.5V
pin 3 - 14.3V
pin 4 - 0V
pin 5 = 4.5V
pin 6 - 14.3V
pin 7 - 13V
pin 8 - 13.6V
pin 9 - 0V
I checked all the switches for Play, Stop, FF/Rew and pause - the are good and function correctly.
The resistors RU02 thru RU017 and RU11 are good.  It looks like Transistors are the only component left.  They must be leaking?

What are your thoughts?
 

Offline Bargainhunter

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UPDATE 2 Marantz PMD430 portable cassette recorder - No Audio
« Reply #17 on: August 18, 2022, 03:30:56 pm »
I just got around the post concerning the voltages on QU01.

I found that there is 0 volts on the emitter.  It looks like the 3.3 volt rail is missing.
I checked the transistor (2SD1020) in circuit with a curve tracer and it looked open. I removed it and checked it on my component tester and it read good.
Again the curve tracer shows open.  The only transistor I have is a NTE293.  The NTE293 reads good on my component tester and good on the curve tracer.
I hesitate to use the NTE293 because it is not an exact match and the Marantz schematic shows this as a critical component.
I don't read any shorts on the emitter connection with the transistor removed.

Is there a better substitute for the 2SD1020?
 

Offline Smoky

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Re: Marantz PMD430 portable cassette recorder - No Audio
« Reply #18 on: August 18, 2022, 04:49:25 pm »
Here's the latest schematic from the 1996 2nd Edition service manual :-+

 

Online wasedadoc

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Re: UPDATE 2 Marantz PMD430 portable cassette recorder - No Audio
« Reply #19 on: August 18, 2022, 06:36:25 pm »
I just got around the post concerning the voltages on QU01.

I found that there is 0 volts on the emitter.  It looks like the 3.3 volt rail is missing.
I checked the transistor (2SD1020) in circuit with a curve tracer and it looked open. I removed it and checked it on my component tester and it read good.
Again the curve tracer shows open.  The only transistor I have is a NTE293.  The NTE293 reads good on my component tester and good on the curve tracer.
I hesitate to use the NTE293 because it is not an exact match and the Marantz schematic shows this as a critical component.
I don't read any shorts on the emitter connection with the transistor removed.

Is there a better substitute for the 2SD1020?
QU01 is not critical, the Zener DU01 is.

What voltages are the collector and base of QU01?
 

Offline floobydust

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Re: Marantz PMD430 portable cassette recorder - No Audio
« Reply #20 on: August 18, 2022, 08:00:33 pm »
Missing the 3.2 or 3.3V rail would make the deck pretty quiet with no power to the audio IC's. QU01 is the 3.3V reg, beta >200 not sure how much current it supplies, highest during record. If it runs hot then there's a short -circuit downstream. Your curve tracer might not be dependable if it says it's open but it's not? The part might be fine.
NTE253 is big TO-92 tall compared to the 2SD1020. I like Zetex E-line parts like ZTX690B BUT they have different pinout EBC ve ECB and hard to get in the semi shortage. You could try the NTE253 to see if it makes a difference temporarily. CU01 1,000uF 6V might have shorted, you can measure the voltage drop across RU01 100R.

JK02 pin 9 goes low when the Pause button is pressed, which turns on mute switch QU02. QU02 collector high at 14V means it's on and muting in Pause mode.
JK02 pin 8 goes low when the Stop button/Auto Stop is pressed, which turns on mute switch QU03. QU03 collector high at 10V means it's sorta on and muting in Stop mode. CU02 leaky, RU03 I think you replaced, and otherwise it's a bit of work to troubleshoot this.

So I'd leave the muting stuff for later, first get the 3.3V rail up and working.


Smokey thanks for the scan. These PMD430 tape decks were out for at least 10 years, pretty impressive for a portable model.
 

Offline Bargainhunter

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Re: Update Marantz PMD430 portable cassette recorder - No Audio
« Reply #21 on: August 18, 2022, 09:21:55 pm »
First let me thank Smokey for the scan and everyone who posted.

The voltages at QU01 are Base 3.2 volts; Emitter 0 volts and Collector 4.4 volts. I removed transistor Qu01 and got the same voltages so I re-installed QU01 and lifted the Emitter from the circuit.  I was thinking QU01 acted like a switch but still got 0 volts on the emitter.  I found out that there has to be a load or drain on the emitter for the transistor to turn on.  I get in the meg ohms when I measure on the circuit board where the emitter should be connected and the ground. RU01 (100 ohms) measures good.
So with all the IC's connected to the emitter of QU01, I should see some sort of load or am I barking up the wrong tree?  I'm thinking an open jumper or trace on the board.
Also zener ZU01 with a 1N4730.  I'm not sure why I reading 3.2 volts instead of 3.9 volts.  I also replaced CU01 - with a 1000uf 10v instead of a 1000uf 6.3v.  The 10v is too tall so I have to order the 6.3v.  I still got the same reading with ZU01 and CU01 replaced.  I also tacked in NTE293 and got the same voltages with 0 volts at the emitter.
It's probably something simple that I'm overlooking.  Thanks for all your help.
 

Offline Bargainhunter

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Re: Marantz PMD430 portable cassette recorder - No Audio
« Reply #22 on: August 18, 2022, 09:25:19 pm »
I also see that the emitter of QU01 goes to the headphone jack and is connected to ground thru a 4.7k resistor when headphones are plugged in.  Could this be a factor?
I don't see how all the IC's on the 3.3v rail are open.
 

Offline Bargainhunter

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Re: Marantz PMD430 portable cassette recorder - No Audio
« Reply #23 on: August 18, 2022, 10:27:48 pm »
Update:  I have no circuit from emitter to pin 5 of JK03.  It is very hard to follow the traces since it is a double sided board with thru-holes and components covering the traces.
It would be nice the see an unpopulated circuit board to show the traces.  There has to be a break somewhere on the board.
 

Online wasedadoc

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Re: Marantz PMD430 portable cassette recorder - No Audio
« Reply #24 on: August 18, 2022, 10:50:22 pm »
Update:  I have no circuit from emitter to pin 5 of JK03.  It is very hard to follow the traces since it is a double sided board with thru-holes and components covering the traces.
It would be nice the see an unpopulated circuit board to show the traces.  There has to be a break somewhere on the board.
Pin 5 of JK03 goes to the collector of QU01, not its emitter.

If you have the base and collector legs of a good transistor connected with a few volts on its base and about 4.5 on its collector and its emitter not connected to anything except your test meter, you MUST have almost the same voltage on the emitter as its base.
 


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