Yupiteru Vt-125 Ii

[Normando Chapman]

Therewere not so many sold in the UK unlike their next model, the MVT-7100 which sold in droves worldwide. Savvy 7000 owners kept their older models, some airfield spotters bought the newer MVT-7100 and were not exactly head over heels in love with it . Out in the field at the side of a runway,or in the immediate vicinity of an airfield the older 7000 seemed to be better than the 7100.

It seemed like the boffins at Yupiteru had taken on board the short comings of just about every other scanner on the market and decided to eradicate all the annoying problems of multiple button presses to do simple things and the issue of badly placed controls which was very common in portable units of the day.

First we have to remove the plastic knobs and unscrew the 3 brass thread collets holding the pots in place into the chassis. Using a sharp flat screwdriver being careful not to slip and scratch the top of the radio. These can be very tight, if you are joining in with your radio..take your time with this, perhaps use masking tape around the openings for protection against slippage.

I say again, be careful here, the rotary encoder with the slotted brass tip is very fragile. It is held on to the control board with solder only now. When the threaded collet is removed, there is not very much mechanical strength to support the encoder .The rotary encoder has very thin legs,which are easy to bend out of line with its mating hole in the top plate of the casing or worse still they could snap off completely leaving you with the horrible job of reinstating it.

The acid gas from the previous owners batteries had migrated up inside casing, so much so there was evidence of acid deposits on the outside 3 of the 6 casing screws holding the radio together. One at the bottom was particularly bad and difficult to remove. The screws go through holes in the plastic casing and screw into threaded metal tabs inside the chassis for structural strength. The screws have to be the right size, any longer and penetration of other components on the PCBs will occur so getting that bottom one out ,in tact, was important.

With all the screws out and the 3 collets out, and the glued on lamp/keylock/reset/contrast legend plate removed its time to lever away gently at the 2 halves of the casing. I used a cut up sim card as plastic shims to gain access space ..easy does it, there are wiring harnesses inside.

A quick dab of solder on the regulator pin and a cleanup of both sides of the 16 way connector with isopropanol cured the faults. To finish off, a touch of servisol switch cleaner was applied to the volume-on-off and squelch potentiometers.

Now, with the back half of the casing stripped out and bare, some much needed repairs to those awful stress cracks mentioned in the first part of this post. the casing is very thin and not very strong at the lower part of the case.

At this point, it looks very untidy but a quick buff with p1000 grit abrasive paper and a bit of artistic flair with a sharpie marker made the fill invisible (from a good distance !). A tiny drop of Greygate plastic polish on a cotton q tip made a nice job of it in the end.

Perhaps I am being unfair, The Uniden UBC-125 series are excellent little radios, they are relatively inexpensive and pack a lot into a small unit. Owners seem to be very happy with them and its good to see Uniden back in the international market again.

I think the MVT-7000 had the mix just about perfect, the only feature missing was a backlit keypad but the ergonomics were so good chances are you will select and hit the right button for the job without even thinking about it.

Hello to my readers from Japan, many of you have contacted me regarding this repair, your feedback and encouragement is much appreciated and I hope that you enjoy the articles. I always like to hear from Japanese avaition radio enthusiasts all of which so far have loved the MVT series radio scanners. They were fantastic machines !

If you are a Yupiteru fan/ owner from Japan consider writing to me using the comments box below and perhaps send some photos,advertising from your country, repairs you have completed or provide some further history regarding the Yupiteru company. Many Thanks.

Hi Ken,

I see you are based here in the UK.

Firstly, I would check the solder joints at the reverse of the 2 pin header and the speaker itself as these were known to be troublesome.

A Namiki speaker is also used in the VT-125 mk2. Unfortunately this loudspeaker is no longer available but you could try a few inexpensive alternatives. You need precise dimensions of the original and try to match.

I have posted a few links below for possible fit.

-electronics.co.uk click loudspeakers section in left menu then select miniature speakers section link here, Bowood Miniature Speakers

Unfortunaltely there are no photos specs.

Alternatively you could try CPC, see Monacor speaker catalogue number LS00533. Lots of other possible alternatives from this company so search their massive online catalogue here CPC Miniature Speakers

The most important dimension would be depth as the main pcb will not fit back into housing if too deep.

You could also try intercom/door phone spares such as Fermax, their speakers are around the right size and tailored for voice communications.

I hope this helps you bring your VT-125 mk2 back to life.

Thanks for your visit.

Mike

Hi there I have just replaced the memory back up capacitor in my 7100 I own two radios the mvt 3300eu and the old faithful mvt7100 both knock the pants off current available scanner receivers on the current market. Nice repair by the way.

Hi,

My yupiteru 7100 cracles evey time there is a conversation with atc which is impossible to understansdw when you do HEAR VOIIVES THEY ARE VERYFAINT I TNINK THE UNIT SI FAULYS AMD WAS WONDERING IF YOU DO REPAIRST-

Hi and thanks for your interest in my blog page.

Sounds like your mvt-7100 isnt behaving right.

These are getting old now mostly damage can be caused due to acid deposits from leaky batteries left in the unit.

This can cause pcb component/wiring short circuits.

I dont take on repairs for others Im afraid due to work commitments but I can recommend someone who does.

I see that you are in the UK.

Graham (aka Radiocruncher) in Devon, England,UK will tackle just about any scanner repair.

You can establish contact from his webpage

Hi.

Nice artice on your repair of the MVT7000! I have just dug out my 7K which I bought as new back in 1992! It has had a hard life and the lower casing around the battery compartment is broken (you are right about how thin the plastic is there!). It was working OK but now it only receives on WFM, nothing on NFM or AM. I am a TV/audio repair engineer so would like to take a look at it.

Do you have any idea where I can find a schematic diagram?

Hi John, Glad you found the pages on my blog useful and you managed to rescue another MVT-7000 scanner and bring it back into use.

From memory I recall that this radio was very popular particularly in the Netherlands. There was a well established Yupiteru distributor based somewhere around Utrecht area, they were probably one of the first to receive stock of each model outside Japan and they supplied clients all over Europe. MVT-5000 and MVT-7000 Very popular with ship spotters at Rotterdam. The UK were a bit late to the Yupiteru party so to speak. Best Wishes John, Mike.

You may think that this user manual would be of no use to an English speaking owner but I have referred to this many times, there are excellent illustrations in this copy and my Japanese has come on leaps and bounds since receiving it !

I appreciate all comments to my blog pages but I have received quite a lot of communications from enthusiasts in Japan and this is fantastic because plane spotting is encouraged so it is not unusual to see lots of spotters with their radios on the viewing terraces at airports in Japan. Security do not discourage use of airband radio unlike other places and there is a large following of the hobby of radio generally..this is great !

In the market of the day AOR/Fairmate had their HP100/200e which had a terrible user interface (an AOR trait in their hand held units which continued on and on for decades),..Icom had their more expensive R1 receiver (I nicknamed it the chocolate eclair of scanners..lovely to look at but very little good inside !) which looked nice enough but was truly awful as it received everything else except the intended frequency.Sony had the Air 7, nicely made, very very expensive and very limited in coverage.

On to this particular MVT-7000, this one has been with its owner for 28 years or so. The owner purchased it from new along with the original OEM soft pouch case accessory which is still in use. Rare item !

As the batteries are inserted, the metal terminal post tangs are forced outwards to the sides of the radio. The plastic casing is very thin and it eventually splits causing the terminals to lose contact and the radio dies with no functions possible.

Some users squeeze the cracked sides back together and this makes the radio work again but also makes the cracking worse until a point where disaster will strike and a chunk of casing will fall off and that makes one very dead radio and a nightmare of a repair job.

If left any longer, a whole chunk of the lower case could have come free and broken away which would make repair almost impossible but thankfully I have caught this one just in time to save it I think.

A piece has broken free from the battery terminal area right in the corner of the casing in this example but not so easy to repair as the user did not refit the battery cover and use an elastic band to secure it immediately. This may have stopped things getting much worse.

I used loctite superglue to work into the cracks widening the biggger cracks first (Yes That IS Very scary indeed) so the adhesive worked its way right down inside then clamp shut back to shape for at least 10 minutes.

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