I'll take a wild guess here. Since it's burnt ...I would say it looks like a surface mount power resistor. The one below it looks unburnt. Put your ohm meter across the chip and see it it reads ohms. Also measure both ways swapping the test leads. It might be a Diode. Just My $.02 worth.
Also, I notice in the upper right hand corner at the end of the string of Big Caps, there is another SMD that looks like the one you show burnt marked in Blue. I see a + sign on the board next to it. Could also be a Cap????
Maybe some one else could offer some more info here.
Mark R
Member
Last Activity: 03-27-2024, 07:28 PM
Joined: 10-20-2023
Location: Egg Harbor Township NJ
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I went to Mouser out of Texas.. They are pretty big.. I have an account there.. Looks like Rewire did all the work I plugged in his numbers and description... [URL]https://www.mouser.com/c/?q=LDO%203.3V%20150mA%20in%20SOT-89[/URL]
This is what I plugged in..[COLOR=#e74c3c][B] LDO 3.3V 150mA in SOT-89[/B][/COLOR]
Redwire to the rescue 👍
You can buy one piece of anything there, Give them a call...Rea Nice Peep's.https://I went to Mouser out of Texa...description......Last edited by Mark R; 12-21-2023, 08:38 PM.Leave a comment:
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Re: Marantz Model 120 Tuner Craziness I am Stumped!
Well I rang out the only JFET in the MPX circuit with the B&K. It was in circuit and tested good. Also the correct voltages are there at Drain Source and Gate.
As far as the silk screen thang ..only one cap was marked wrong. It blew up the moment installed it according to the silk screen (+) marking.
As I removed each cap one by one I made note of the (+) marking. I also tested each one out of circuit with the LC102. Then Test the new one to be installed.
So one...Leave a comment:
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Re: Marantz Model 120 Tuner Craziness I am Stumped!
That would be the Marantz 120....Leave a comment:
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Re: Marantz Model 120 Tuner Craziness I am Stumped!
I did pick up a 150 and also bought the MPX IC's. The original ones form Hitachi
I put them in my stock. I found one guy that wants $300.00 to do an alignment. Not gonna happen. You can't even talk to him on the phone. You send him an email and a week later he answers. That's how busy he is. He only does retro gear.
I found a Local guy that has some one that will do the alignment cheaper and has the proper equipment. He works for a Local repair shop two days a week. Waiting on a call from...Leave a comment:
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Re: Marantz Model 120 Tuner Craziness I am Stumped!
Petthall and Redwire thanks for your help. Gonna side line this 120 unit for a while and move on to other projects. Got a line on a Sencore SG-80. So if the price is right I'll pick it up and fark around some more.
On an another note....I did pick up a Marantz 150 tuner used cheap in great shape. Seems original. It's back in my All Marantz separates system.
Again I'd like to thank Redwire, Petehall and Badcaps web site for your excellent help and time.
I haven't given up yet on the 120...Leave a comment:
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Re: Marantz Model 120 Tuner Craziness I am Stumped!
I think I'm ready for one of these.....Leave a comment:
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Re: Marantz Model 120 Tuner Craziness I am Stumped!
Yep First thing is not to mess with alignment. As you say I always head to PS First thing Then it's the P300 Board.
The 2252 is a nice unit. I've recapped many Marantz's. Big improvement. I do use the color tool in the PDF with the help of "Paint ..Microsoft" by blowing up the section and having Paint in printer set up do the whole page. It prints out both Half's and then I trim and put them together with tape. Makes it allot easier.
BTW. That Skid at the bottom for the 120...Leave a comment:
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Re: Marantz Model 120 Tuner Craziness I am Stumped!
Here's what I got...J305 is .025 to chassis ground
...........................H306 Collector is .429 To Chassis Ground
...........................H307 Base is .067 to chassis Ground
............................J303 is good @ 12.70 Vo,ts to chassis ground
H552 Base .581 To Chassis Ground
" Collector .069 Volts to chassis ground.
" Emitter O Volts to Chassis Ground.
I can't get to the cap C559 "Disc"...Leave a comment:
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Re: Marantz Model 120 Tuner Craziness I am Stumped!
Thanks Pete:
Will check that out. I think I already tweaked that pot but I'll go back and look at it again....Leave a comment:
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Re: Marantz Model 120 Tuner Craziness I am Stumped!
Thanks Pete. I have two twin lead 300 ohm FM antennas. One is in my garage with the Marantz 4240 and I have the other one on the bench with the Marantz 120 were working on. It is strung out like the Letter "T" Dipole style.
You say.. Which pot are you talking about? And what other pot are you speaking about for adjustment without test equipment?
I haven't tried putting the case back on but at this point I'm ready to try anything.....L.O.L.
As stated ...FM Mono...Leave a comment:
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Re: Marantz Model 120 Tuner Craziness I am Stumped!
Gheeeeeeeeeez. Never noticed the other Skid... Mine is Serial # 1077 which means I was on the wrong Skid.
And it is torcher. I have blown up the skids and did a Print screen and taped the two large blow ups together. I'll have to go back and check the bottom skid. .. But your correct... it's hard to do this over the web. And, I think you are correct..it something with P300. It's a weak FM MPX signal.
You have to tune up or down to find the sweet spot to keep the lamp lit. It is hitting...Last edited by Mark R; 11-05-2023, 08:32 PM.Leave a comment:
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Re: Marantz Model 120 Tuner Craziness I am Stumped!
Update Sunday the 5th. It now seems to be hitting all FM stations with Stereo ..But the signal doesn't seems to be strong enough to keep the STEREO Lamp lit. If I rock the fly wheel tuning knob I can get it to modulate with the voice or music. But it won't stay solidly locked.
Your ball.... if you haven't left the building ...
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Re: Marantz Model 120 Tuner Craziness I am Stumped!
Originally Posted by redwire View Post
I need to know if it can receive FM MONO okay.
Then it is either the FM Stereo enable that is screwing up now, or it just can't have enough signal for stereo. The distortion is the thing to figure out, unless it's just weak signal - which would also show up for mono.
I have a Mono station tuned in now. Good strength. Mono display on the scope(Diagnoal Line) strong. But when I switch to stereo ...it doesn't show it. Not sure if this is a stereo station as it is Talk...Leave a comment:
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Re: Marantz Model 120 Tuner Craziness I am Stumped!
Here's a Video of the 120 not doing it's thing. When it tunes the stereo light goes out you off tune a hair it'll flicker. Allot of stations not pulling in stereo at all.
[url]https://youtube.com/shorts/u_nkyBjIIS0?feature=share[/url]Re: Marantz Model 120 Tuner Crazines....com/shorts/u_Leave a comment:
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Re: Marantz Model 120 Tuner Craziness I am Stumped!
Here's a Video of the 120 not doing it's thing. When it tunes the stereo light goes out you off tune a hair it'll flicker. Allot of stations not pulling in stereo at all.
[url]https://youtube.com/shorts/u_nkyBjIIS0?feature=share[/url]Re: Marantz Model 120 Tuner Crazines...tube.com/shortLeave a comment:
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Re: Marantz Model 120 Tuner Craziness I am Stumped!
Ok I'll check the above out.. Here's my PDF version which looks about right,...Leave a comment:
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Re: Marantz Model 120 Tuner Craziness I am Stumped!
Ok..First of there is no Signal strength meter..just the scope which shows (In Audio Mode) the signal with mono display in audio.
As I tune I can hit a station which will cause the stereo Lamp to flicker on and off but not solid on that station (The Lamp Lights the Name "STEREO" on the front panel.
When it flickers the scope will show a Stereo Display intermittently. Very few Stereo stations will trigger the lamp maybe 1 or two. The actual audio is not clear but fuzzy. Some...Leave a comment:
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Re: Marantz Model 120 Tuner Craziness I am Stumped!
OK Redwire... This ones for the Books.... I was checking point to point wiring from the P550 board to the MPX board P300.
When I got to J555 on P550 and followed it back to P300 the skid shows a connection at J504....
Well Dam..?? There is no stand off terminal J504 on P300 on the top side?? So I look on the board and there is a Marking for J504 which is a small thru slot cut into the board . No Terminal.
So I flip the board over and there is a white wire which looks...Last edited by Mark R; 10-30-2023, 03:52 PM.Leave a comment:
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Re: Marantz Model 120 Tuner Craziness I am Stumped!
In reverse,,,,,,,, No I don't think the Quad thing made it to FM.. Same as discreet 4Ch sound from records,,, Only Panasonic figured that one out with theit CD-4 system and the use of there demodulator and the Audio Technica
Cartridge and Sahbata Styles.
Sanusi Faked it with There "SQ" sound that really wasn't discreet 4 channel.
Any way ..Back to reality.. Ok I'll have to attack this tomorrow and do the measurements. What a Complicated system...Gheeeeeeeeez.
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