UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players

Notices

Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

Closed Thread
 
Thread Tools
Old 23rd Nov 2022, 5:45 pm   #1
sourbiscuits
Pentode
 
Join Date: Sep 2022
Location: Amsterdam, Netherlands.
Posts: 124
Question [NEED ADVICE] Marantz CP430

Ok, so I was going through the unit to see if I could troubleshoot a problem with the pitch control not working. It took me a while to spot this swollen capacitor next to the power supply input. Do you think it might be related to the issue and even if not should I worry about it?
Attached Thumbnails
Click image for larger version

Name:	IMG_20221123_174439.jpg
Views:	132
Size:	124.1 KB
ID:	268618   Click image for larger version

Name:	IMG_20221123_174426.jpg
Views:	119
Size:	95.7 KB
ID:	268619  
sourbiscuits is online now  
Old 23rd Nov 2022, 6:29 pm   #2
Station X
Moderator
 
Station X's Avatar
 
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,192
Default Re: [NEED ADVISE] Marantz CP430

With its end bulging like that it definitely needs changing. Whether it will fix your problem I cannot say.
__________________
Graham. Forum Moderator

Reach for your meter before you reach for your soldering iron.
Station X is online now  
Old 23rd Nov 2022, 6:43 pm   #3
paulsherwin
Moderator
 
paulsherwin's Avatar
 
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,787
Default Re: [NEED ADVISE] Marantz CP430

Absolutely, that is a very sick capacitor. Look carefully at any others from the same manufacturer with similar values too.
paulsherwin is online now  
Old 23rd Nov 2022, 6:47 pm   #4
sourbiscuits
Pentode
 
Join Date: Sep 2022
Location: Amsterdam, Netherlands.
Posts: 124
Default Re: [NEED ADVISE] Marantz CP430

Thank you kindly for the replies!

Quote:
Originally Posted by paulsherwin View Post
Absolutely, that is a very sick capacitor. Look carefully at any others from the same manufacturer with similar values too.
What do you mean with the second sentense? Does that refer to the replacement cap I will look for or for any other bad ones on the unit?
sourbiscuits is online now  
Old 23rd Nov 2022, 6:52 pm   #5
paulsherwin
Moderator
 
paulsherwin's Avatar
 
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,787
Default Re: [NEED ADVICE] Marantz CP430

No, look for any similar capacitor from the same manufacturer ALREADY PRESENT that might have failed. Look for any sign of bulging or leakage. If anything is suspicious, change.
paulsherwin is online now  
Old 23rd Nov 2022, 8:53 pm   #6
Chris55000
Nonode
 
Join Date: Aug 2007
Location: Walsall Wood, Aldridge, Walsall, UK.
Posts: 2,853
Default Re: [NEED ADVICE] Marantz CP430

The pitch control RS06 varies the control potential on pin 2 and Pin 3 of QM01 (AN6612) on PCB ref. PM01 and the defective electrolytic could certainly affect the operation of this device, but I can't pick it out on the rather grotty scan of the service manual!

The control RS06 is a special centre–tapped type connected in such a way that it varies the nominal speed of the motor above and below the nominal centre–point setting, which occurs when the wiper of RS06 is adjacent to the centre–tapping on the track of RS06.

A contact on the record/playback switch is provided to automatically take the pitch control out of circuit on the "record" position since (under normal circumstances!) you always want the recording speed to be at the correct nominal figure of 1⅞ i.p.s!


Service Manual :–

https://www.manualslib.com/manual/11...ntz-Cp430.html

AN6612 Datasheet :–

https://www.alldatasheet.com/datashe...IC/AN6612.html

Replacement Device :–

https://www.ebay.co.uk/itm/201618747...mis&media=COPY

Don't forgot to test the pitch potentiometer RS06 itself with a multimeter, and the wiring to it between boards RS01 and PM01 (see circuit diagram in manual)!

Another possibility is a fault in transistor QM02 or the motor sense resistors RM01 and RM02 but I suspect a fault in these components would affect normal playback as well!

Chris Williams
__________________
It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed!

Last edited by Chris55000; 23rd Nov 2022 at 9:03 pm.
Chris55000 is offline  
Old 23rd Nov 2022, 10:28 pm   #7
sourbiscuits
Pentode
 
Join Date: Sep 2022
Location: Amsterdam, Netherlands.
Posts: 124
Default Re: [NEED ADVICE] Marantz CP430

Chris, I was quite hopeleaa I would be able to find a component fault in all honesty. I was hoping on a bad solder point or bad connection. I cleaned the pot with contact cleaner. The very strange thing is, the pitch knob was engaging at random occasions a few times since I got the unit. I thank you for the detailed information. I will have a look at it again! I will keep you posted and let me know if the random behavior of the pot tells you anything more.
sourbiscuits is online now  
Old 24th Nov 2022, 9:29 am   #8
untune87
Pentode
 
Join Date: Oct 2010
Location: Greater Manchester, UK.
Posts: 161
Default Re: [NEED ADVICE] Marantz CP430

Mine had the same problem; pitch control didn't work. I found that the big power cap had burst and leaked on mine, and it had leaked into one of the big 8 or so pin connectors that seemed to be causing issues. After replacing and cleaning, IIRC the pitch control did start working again, but the last time I used it, it had stopped again.

I think it was an ealry lockdown project that I'd had sitting in a drawer for a few years, and I can't remember if I made notes... but I tend to take lots of pictures, especially with something like this, so I'll check my phone for clues.
untune87 is offline  
Old 24th Nov 2022, 12:25 pm   #9
sourbiscuits
Pentode
 
Join Date: Sep 2022
Location: Amsterdam, Netherlands.
Posts: 124
Default Re: [NEED ADVICE] Marantz CP430

Thank you again for the replies to everyone. Here is what I did so far:

I first did a continuity check on the wiring between PM01 and PS01 (I presumne this is what Chris meant instead of RS01) as suggested. All good.

As suggested by Paul, even before I posted the thread I went over all the caps I could see with a naked eye. Did a very thorough inspection. I could not spot anything visually concerning. There is yellow substance which I believe is industrial glue (see photo). The only place I did not check is the two mounted PCBs on the photo with the black wire passing along.

Then I did a resistance check of the trim pot. Starting like shown on the photo I got the following readings:

First two pins connected I get 55 ohms with the pot all the way to the left, 54 when centered, 0.7 all the way to the right.

Pins 1 and 3 give no reading unless I place the pot close to the far right position. Then I get 61.5 ohms and it goes up the closer I get to the center with a max value reading of 200 ohms before it stops reading.

Exact same situation happens between pins 1 and 4 where the center position reads a 60 ohm resistance, rotating left increases the value, right decreases.

Pins 2 and 3 gave me a 0.6 ohm R in the center.Left increasing the value, right also increasing the value.

At this point of the test I can assume the trim pot is of a 200 ohm value and I think it functions as intended.

Taking the above out of the way, I want to deal with the bad cap. It's a 2200 uF, 10v. I called at a store today to ask if they have it and they do but in 16v instead of 10. Would that fit?

Last but not least, the IC AN6612. Could I perform any sort of troubleshooting to confirm if it's faulty or not? I've got a rather basic multimeter (see photo).
Attached Thumbnails
Click image for larger version

Name:	316003808_1100702627302770_5512845104609183690_n.jpg
Views:	40
Size:	102.5 KB
ID:	268650   Click image for larger version

Name:	316136541_824615798775365_495122395884158999_n.jpg
Views:	47
Size:	64.6 KB
ID:	268651   Click image for larger version

Name:	316018123_492054392990803_6918901233506544603_n.jpg
Views:	45
Size:	102.4 KB
ID:	268652   Click image for larger version

Name:	316416629_529671628763726_2776586947886149934_n.jpg
Views:	31
Size:	82.6 KB
ID:	268653  
sourbiscuits is online now  
Old 24th Nov 2022, 4:28 pm   #10
sourbiscuits
Pentode
 
Join Date: Sep 2022
Location: Amsterdam, Netherlands.
Posts: 124
Default Re: [NEED ADVICE] Marantz CP430

Solved! Now Chris mentioned a switch that turns off the pitch control out of the circuit when REC is engaged. If you go back to my first post and look at IMG_20221123_174426, you will see that switch between the faulty cap and a red component. I've been looking at that switch for a while and wondered what it's meant to do as it was quite detached from the mechanics. After I replaced the cap today, the unit was on and nothing seemed to have changed. The moment I touched that swtich the pitch control suddenly started working again. I then realised, there is a pin attached to the mechanical REC switch that pushes that switch down when recording. That also engages the erase head. Apperanlt, the problem was there. I think it has a bad contact/is dirty. I used some contact cleaner there too. The reason why the pitch did not work is simply becaus I did not trigger the REC button in all these tests. I think that is what user untune87 might be experiencing as well. Worht to check that out.


While I still have the unit opened, I wanted to ask about the volume knob. It seems to cut out the right channel of the headphone out and for the speaker as if I switch to R only there is no output. I've managed to find two sweet spots where the pot will output from both channels. Unfortunately the pot has a long shaft and isn't a regular one. I've cleaned it twice already without much succes. Do you think there is a way to repair it or I should definitely look for a replacement?
sourbiscuits is online now  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 12:20 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.