Yet another Yupiter0 MVT7100 problem.

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Seikowatchman

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I'm back after a while away from the radio scanning scene having been rather disappointed with a Radio Shack scanner ( I can't recall the model but it wasn't the easiest piece of kit I've ever used. Then I had an AOR unit which was a vast improvement. After some long drawn out cancer treatment and an interest in building electronic devices for the grandchildren I recently bought a Yupitero MVT7100 from the dreaded Ebay. £45 which at the time seemed a bargain as all it apparently needed was a replacement memory capacitor/battery.

Taking it apart was easy after studying several Youtube videos. I was however surprised to find when measured the voltage across the item was 4.5V. Not too far off the normal 'fully energised' 5V. I replaced it and also re-soldered the speaker and battery connecting wires which had been previously poorly soldered in place by whoever fitted the previous capacitor/battery. It made no difference at all. The scanner receives perfectly but refuses to remember anything. Total amnesia !

I have thoroughly cleaned the keypad contacts and carefully cleaned the keypads themselves. Everything else works except its memory. I even get the 'double beep' to say it's all been entered correctly but I still get 'clear' displayed when I start it up.

Any suggestions as regards anything else I can check before I have to admit defeat and put it in for repair would be hugely appreciated.

Thanks for taking the time to read this,

Chris.


 

prcguy

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There is a capacitor that holds the memory instead of a battery and they all need replacement by now. You can find info in the Internet on how to do this and its fairly easy. The capacitor is available from many sources including eBay.
 

Seikowatchman

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Hi prcguy,

Thank you for your response but as stated in my initial post I'm aware of this capacitor and have already replaced it. It's made no difference. Everything else appears visually to be OK. I have a 7100 Service Manual but it's mainly parts lists, schematics and assembly drawings. No actual circuit fault finding information.

What I need to know is where to look next now I've replaced the capacitor but still can't store any settings.

Chris.
 

Seikowatchman

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Hi racingfan360,

Thank you for your suggestion. Yes, I tried the reset as soon as I first discovered the problem. Even though the original capacitor/battery was showing a decent voltage I went ahead and replaced it. A surprisingly straightforward thing to do.

Sadly it made no difference and I still get the CLEAR message upon switch on.

I contacted Nevada in Portsmouth but they're currently only taking warranty jobs. The scanner is otherwise perfectly usable but a memory facility would come in handy if I decide to listen to more than Gatwick Airport which is only a couple of miles away.

I thought maybe someone else might have had this fault and be able to point me in the right direction. Failing that does anyone know of someone in the West Sussex or surrounding areas who might be able to sort it out for me ?
 

racingfan360

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I suspect this wont be a straightforward fix Chris. Perhaps two other things to try:
1. Are the batteries being held really securely in the compartment? I had an issue where the my 7100 would reset each time because of missing rubber pads behind each of the metal tabs that help push the contact with the batteries = loss of connection = reset. If you have a power supply try that as well to see if it helps.
2. You might need to reflow some more solder joints if they have failed, such as those described here (the 7000 is similar to the 7100): Scanner Greats.. Yupiteru MVT-7000 brought back to life ! – Mersey Radar

Failing that I suspect that buying another 2nd hand one off ebay will be cheaper than a repair. They tend to go for £100-150.
 

Seikowatchman

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Many thanks racingfan360 for taking the time to send me such an informative response. I followed both threads and picked up not only some interesting things to try but it was also an interesting read. I've heard from several 7100 owners that the standard of soldering leaves a lot to be desired. The solderIng on my particular scanner looks as though someone has already attacked it with something hot ! There were splashes of solder everywhere. I cleaned all the circuit boards up but I've been putting off any re-soldring until I at least knew which pcb I should be concentrating on.

The other factor is that the scanner works perfectly apart from the amnesia so I've been reluctant to do anything too drastic in case I make the problem worse.

Having said all that, the scanner only cost me £45 to begin with plus £3 for the battery/capacitor and another £12 for the mains power supply.

Looks like some re-soldering is the next step. 😊

Thank you again for your response. Much appreciated.

Chris.
 

Seikowatchman

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I stripped the scanner down again and carefully (very carefully) re-soldered all the dry/dull/crumbly looking soldered connections. All three circuit boards thoroughly cleaned and several solder 'whiskers' removed. Pins and connectors cleaned and everything carefully reassembled. Result . .

Exactly as before. CLEAr coming up immediately on the, albeit now much cleaner and brighter, display. I can only assume one or more of the components have failed and no amount of re-soldering or PCB cleaning is going to fix that.

The scanner still receives perfectly on all modes so it looks like I'll just have to live with it. Alternatively I could put iit in for a probable costly repair or buy another one either as a source of parts or as a replacement scanner.

Many thanks though to the forum members for the assistance and advice I've been offered.

Chris.
 

racingfan360

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So a bit more digging Chris.....
"The memory in the 7100 is retained by a Goldcap capacitor of 0.22 F at 5.5 V. It's a small cylinder about 1 cm in diameter and 0.5 cm tall"
"It is a horizontal PCB mounted component and whilst replacing it not difficult does require disassembly and de-soldering/soldering skills."
Panasonic Gold Capacitor SD Series
Panasonic # EECSOHD224H


Maybe worth a go?
 

Seikowatchman

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Hi racingfan360, if you look back through my earlier posts you'll see it was the first thing I replaced.

I even replaced the replacement capacitor/battery in case I'd been sold a dud one.

After nearly 47 years as a field service engineer working on almost every type of scientific and medical equipment there is and often replacing components on pcb's my soldering skills are excellent so no problems there for me. Unfortunately however my knowledge of radio scanner repair's is nil.

Failure of the capacitor/battery is well known and on the Yupi 7100 its replacement is a simple job capable of being done by anyone with a steady hand and even basic soldering skills.

To sum up, the capacitor/battery has been replaced, the 'reset' has been tried, all the suspect looking soldered connections have been remade. The battery connections are fine but even when using a mains PSU the scanner still won't allow me to store anything.

I now believe the fault to be a failed component, or components, but without the required specialised test equipment and a service manual I can go no further.

Chris.
 

racingfan360

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Ah sorry Chris I misread that, thinking you'd replaced an alternative capacitor. I think we've exhausted the likely options.
 
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