Mark R
Senior Member
Last Activity: 09-07-2024, 11:54 AM
Joined: 10-20-2023
Location: Egg Harbor Township NJ
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Disregard the above pic's I posted them hear by mistake.... -
Ok Ill post the pic's I took. I did earlier but in the wrong place... They look close but there good. Unit is working fine. I'll just leave it be. [ATTACH=JSON]{"data-align":"none","data-size":"large","data-attachmentid":3294944}[/ATTACH] [ATTACH=JSON]{"data-align":"none","data-size":"large","data-attachmentid":3294945}[/ATTACH] [ATTACH=JSON]{"data-align":"none","data-size":"large","data-attachmentid":3294946}[/ATTACH]Ok Ill post the pic's I took....
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Sounds like a winner... Not up on the Chinese devices. But it has to do modulation Pilot freqs and all the stuff that a Standard alignment generator would have to do. I picked the Sencore up for cheap about $140.00 not counting shipping.. I collect old Vintage test gear. I'm still looking for the Digital Version which was the newer model. The SG 80. That unit is sought after by most techs and are like hens teeth.
One went up on Ebay and lasted 10 Min. I missed it as it sold before Ebay could notified me as I have it on my Favorite List and it went fast before I could get the notified....Leave a comment:
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Well I found a Sencore SG165 with the original Box and manual and test leads on Flea Bay. Also downloaded the full manual which has calibration and skids and well as operation ... 71 pages. Looks clean Except it does power up. He had pics of the insides which looked very clean. I'm guessing the power supply is farked. Probably caps or something minor in the supply.
So I gave it a shot and pulled the trigger. When I get it working and calibrated which looks simple I might learn something. I'll put my self thru school and try to do the Marantz 120 and do my first alignment. I know...Leave a comment:
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Hey Great Sage,
Been busy and haven't had time to reopen the tuner to check for that solder bridge. I'll try and get to it tomorrow. Thanks
Mark R...Leave a comment:
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Ok..Now Ise what your talking about. Ok I'll pop the cover since it's back together and take a Look. Thanks for the Photo and location. Get back to you soon...Leave a comment:
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You call it the display Controller???? Are you speaking about the large Postage stamp IC Chip? Can you post a pic from mine that indicate what you are talking about?
Also All solder joints on the VFD are perfect. They were looked at with a Jewelers Loop. All caps were changed out after testing. Two were bad. All solder joints are perfect on the front panel control board....Leave a comment:
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Yeah that's one way.. But I rather have the SENCORE SG80....But they are no where to be found for sale in the world.... Real Hens Teeth....Leave a comment:
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Are you speaking about the Main Multi pin IC? Between Pin 51 and 50? Post a picture from mine so I know which photo your speaking about.
Also: The unit seems to be working now since I changed out two caps... Thanks for leading me to that area and the link to The VFD display site and every one here who helped me.
Here is a pic of the now brighter display. Why they shove a Hunk of Red filter in front doesn't make sense to me. I guess they want to hide the circuitry in and around the VFD. It looks better in it's Natural color.
[ATTACH=JSON]{"data-align...Leave a comment:
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At the time of the pictures I had not touched or soldered anything. Where are you indicating?
As of this time 12:05 AM EST I located the problem. It was a 6.3 Volt 1000 MFD cap on the display board. The LC103 showed Leakage and also showed high Dielectric [URL="https://www.pveducation.org/pvcdrom/pn-junctions/absorption-coefficient"][COLOR=#000000]Absorption[/COLOR][/URL]. I replaced the cap and the display now is much brighter. I used a 1000 MFD @10 Volt cap. Seems to be working ok.
Now what is really ticking me off is one button fell out of the front panel...Leave a comment:
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Thanks... Yep all caps were changed... If I had known that I would have left those caps along. I don't have any AM/FM alignment equipment. I have everything else but. I was looking to pick up a SENCORE SG80. But they are none around. I do have the Service manual but that procedure is very involved. I was going to spend the money for a Alignment unit but I think I'll pass.
Since I have never done an alignment but have seen it done on Youtube, It's involved. In all my years of electronic repair I have never done an AM/FM alignment. I think I'll pass. The unit is now on Ebay for Repair...Leave a comment:
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Ok Sam Sam Sam.. Here are some Pic's showing the unit broken down. There are a bunch of caps on one side of the board. Also I don't see any indication of 3 Volts A C on the board . Just 5 Volts and I think 31Volts. But it does read as DC Voltage.
So Next step is to get out the LC103 Cap Checker and Fire up The MBT-250 De solder station.
I'll check back after I check these caps.
Regards: Mark R [ATTACH=JSON]{"data-align":"none","data-size":"large","data-attachmentid":3289098}[/ATTACH] [ATTACH=JSON]{"data-align":"none","data-size":"large","data-attachmentid":3289099}[/ATTACH]...Leave a comment:
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Will do Sam Sam Sam ,, Been busy running around. Haven't been at the bench. I'll try and rip into it tomorrow. I hate when guys help you out and then that person who needed the help never answers back. That's Not me. I appreciate you guys and I will keep you posted. I'll take a few pic's when I find the problem. Thanks Guys..
Regards: Mark R...Leave a comment:
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Does Changing Out Caps In A Tuner Effect FM Reception
"TQ" Subject at hand is a Marantz 120 tuner. The tuner lit up but no output. Recapped the entire unit. Before it was working fine tuning in Stereo and Mono. Now it just about tunes Stereo and some of the mono stations are weak. Nothing else was changed. When you do hit a stereo station the stereo lamp will come on but flickers as it's trying to hold the MPX signal.
I don't see how bringing the unit back with new caps checked by my Sencore LC103 would effect the FM section. Every Value is as it was from the factory?
Any Thoughts? -
Thanks For the reply Sam Sam Sam
As you say Been there done that..L.O.L. The ribbon cable is the removable type or plug in with a release tab on the main board. So no problem there.
I am able to remove the entire front panel complete. It's held in place by about 10 screws. Luckily I have a good Small power Screw driver...
( Panasonic) which works great.
Also...Yep... the dreaded cold cracked solder joints. I also have a 10" screen LCD Microscope for working on SMD's. So I can see a small SMD Resistor which the scope makes it look like the size of a...Leave a comment:
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Great ..Got it... Will review and Operate on the Patience......Leave a comment:
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Thanks 齊天大聖,
Thank you for the starting place. I have had my share of cold joints. Wave soldering does it every time. I have a PACE MBT 250 Solder-De Solder Station and a Hot Air Unit for SMD Devices. So I should be able to locate the problem.
Interesting that they use a heater in the VFD. Now I can see why. If I locate a 3 Volt AC rail in the chassis plug feeding the Main front panel display board I should be able to run it down to a Cap as you say.
I didn't notice an AC feed after the ac to dc conversion in the back end. I'll check the back end...Leave a comment:
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Thanks Great Sage,
So it is a vacuum fluorescent display. It's made up of many small dots that form the Letters and numbers. As far as a Schematic goes , Its hard to find.
I'll have to search for one again. I assume that Bad Cap.. Should be on the main Display Board behind the front panel with the Postage Stamp Driver IC Chip.
Did a quick look at the caps and nothing bulging up. Got My Sencore LC 103 Cap checker so it'll be pull and check if I can narrow the location down of the cap. Wonder what kind of voltage is used to drive the VFD??
Any Ideas?...Leave a comment:
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Equipment Display Types
Most Displays I have worked with are of course LCD Or Blueish Fluorescent Types. I Have a Marantz PMD800 tuner with sort of a white display. The display area is a sealed rectangular shape in a Glass Case. Looks like some sort L.E.D. display only not your typical section number type. I picked up this Tuner cheap as the display is very Dim. In front of the circuit is a dull red Plastic lens.
The display is very week and hard to see. I've got my DC 5 Volts allover and also a DC 32 Volt that runs some other section. Power supply looks good front to back. Not familiar with this type... -
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.Leave a comment:
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