Electronics – Page 11

Big Trak CE3962 restoration

I refer you to the post I wrote earlier in June 24: Teenage jealousies revisited

Here I purchased the toy I most wanted back in my teenage years. Unfortunately I wasn’t available to get the original MB version produced in 1979 so I had to settle for the latter “improved” version made by Zeon Ltd that was made in 2010.

It’s arrived and to be honest dosen’t look too shabby, needs a bit of a clean up and maybe some new transfers applying but we’ll get to that at another time, for now we need to try and get the machine up and running.

I’ve eventually managed to get the lid off. This unit was built to ensure that it was difficult to get into so repairs couldn’t be carried out. Some of the screws are buried under fascia dressings, and if you aren’t careful you could end up snapping some of the body shell.

With the two halves of the body shell detached it’s obvious there are some detached wires. One was a battery wire, one was a speaker wire. Oh if this was the issue wouldn’t it be great? But it wasn’t. I soldered these wires back into place, put the three D types in place and it was still dead.

I’ve now desoldered all connections from the circuit board to assist in carrying out checks for continuity and tracing voltage. I can also check the board under the microscope. I may change all the capacitors for SMD ones.

I started checking continuity and tracing voltages and was doing really well until I got to a large section of the main board where everything seemed dead and unresponsive. What the heck was going on here? And then I noticed the wire had detached from the positive probe of my multimeter thus ending any further testing for today. I need to order some new probes. Well, I’ve ordered some nice new probes and croc clip connectors as well, so as soon as they arrive I’ll get back on with the testing. They arrived and were damaged on arrival, so back to the drawing board.

I took the drive train to pieces and here it became apparent that a number of the cogs are damaged. I believe there is also some issues with the motion detector but I can’t confirm that until I get some power into the motors. I can’t find spare cogs online so I have ordered myself a second damaged unit to use as salvage. To be honest this new unit has all the transfers in place so I will probably use that shell and the guts of my original unit to form one complete Big Trak.

New donor Big Trak – better than my original one

The donor unit has arrived and boy I’m impressed. It’s in far better condition than my original one, so as expected this one will become the working unit and my original one will be come the donor. Any parts left over will be sold on as spares or even used on another damaged one if I can source it.

My new Bigtrak

If you look at the video above you will see the new Big Trak going through the motions. However the one thing it dosen’t do is turn. Could be a wheel sensor issue who knows. Good thing is that the cogs haven’t broken as the drive wheels are both solid and not free wheeling.

There are only two real issues with the donor here. Firstly it will not do the turn command and secondly, one of the drive wheels is damaged. Luckily I have a spare wheel so this was swapped over, some decals were missing but I coaxed these off my old truck with a hot air gun and reapplied them with no issues.

Looking into the drive issue meant opening the gear box. In here we have two magnetic independent gear controls that should have a gap between them, these two were stuck together thus rendering independent motor operations of the turning control useless.

I removed the two motors and repositioned them and the cogs holding the magnetic gear, this gave a gap of about 3mm that now allows the wheels to turn in opposite directions allowing the unit to turn.

Now the Magnetic sensors are adjusted….it turns

Whilst in this gear box I was able to confirm the issue with my old gear box and it really is all down to two damaged drive cogs that I need to obtain. I’m pleased with that as I could now get two good working units for just a small outlay once I can source some cogs. I will have to repair the wheel I removed to replace the one on my new unit however I have an idea how I’m going to remedy this and again it’s a low cost option. But that’s a job for another day.

2:18 of rebuild magic

So if you look at the video above, it’s the full fix that I posted on YouTube. Really pleased with this fix, again I’ve learned quite a bit about these units and I’m going to have immense fun programming it. My wife dosen’t understand my excitement over this toy, but all my old buddies and colleagues understand it as they grew up in the same era. Maybe it’s the male menopause, reliving the past and all that.

But hey, it keeps me occupied and out of mischief so who should worry about that

This one is going on my shelf so when the kids visit I can show them the joys of basic programming we experienced back in the day.

Job done.

Slow scan television on an iPhone

There is a form of amateur radio comms that I enjoy and that is slow scan television. Here’s a basic explanation:

A literal term for SSTV is narrowband television. Analog broadcast television requires at least 6 MHz wide channels, because it transmits 25 or 30 picture frames per second (see ITU analog broadcast standards), but SSTV usually only takes up to a maximum of 3 kHz of bandwidth. It is a much slower method of still picture transmission, usually taking from about eight seconds to a couple of minutes, depending on the mode used, to transmit one image frame.

Since SSTV systems operate on voice frequencies, amateurs use it on shortwave (also known as HF by amateur radio operators), VHF and UHF radio.

Wikipedia

In this Instance below I used a digital transceiver and was pointing the aerial in the general direction of the International space station as it passed overhead on a specific date, when the Russian section of the ISS was transmitting slow scan television pictures as it passed over. I used my iPhone to decode the signal and to produce the pictures, using an app I had installed earlier. This was all part of a day celebrating the anniversary of Sputnik, the world’s first man made transmitting satellite.

My setup was totally mobile and so basic that I just about managed to get partial scans via this technique, see the two pictures below. I was literally sitting in the front seat of my car.

The picture I received from the ISS and my radio

Even though my pictures were not perfect I was still able to supply proof that I received the transmission and as a result was issued with the certificate below from ARISS – Amateur radio on the International Space Station, find out more about ARISS Here: ARISS

There are many of these types of events that occur all year round where you can experiment with all types of equipment to make contact with distant radio stations. This is the spirit of amateur radio.

Teenage jealousies revisited

I’ve just brought one of these, it’s a toy and I’m heading for the senior end of adulthood:

BIG TRAK / bigtrak is a programmable toy electric vehicle created by Milton Bradley in 1979, resembling a futuristic Sci-Fi tank / utility vehicle. The original Big Trak was a six-wheeled (two-wheel drive) tank with a front-mounted blue “photon beam” headlamp, and a keypad on top. The toy could remember up to 16 commands, which it then executed in sequence. There also was an optional cargo trailer accessory, with the UK version being white to match its colour scheme; once hooked to the Bigtrak, this trailer could be programmed to dump its payload.

WikipediA

Here’s what the original listing said:

Item probably does not work. I recall attempting to fix corroded terminals years ago and it’s still not working. I do not have D cell batteries to test now.

EBay

I was just browsing around as I do and this popped up on my timeline, the wife is going to disown me for bringing such junk into the house, however for a split second 14 year old me was in the house and a flood of memories, not all good came back to me. These toys came out in 1979 when I was aged 14. My friend over the way from me was brought one of these for Christmas and I experienced one of my first ever episodes of Jealousy. Back in 1979 I believe they retailed for approximately £39 Gbp, and my parents weren’t about to part with hard earned cash to invest in developing technology like computing – “It’ll never last, it’s just a fad” (Famous last words).

I made every excuse possible to go around his house to play and even offered to look after it for him when he went on holiday, he never let me though and I believe at that moment my friend realised what the term obsessive meant, as he was experiencing it big time with me.

Now I own one, however this is the later version from 2010, it only cost me £9.99 Gbp and its probably a wreck, but I’m really going to treat this like a proper full sized car restoration and I want this to work, crikey I’ve even found out I can buy the original decals from Australia, so it’s patently obvious the obsession is still there.

I can’t say I have genuinely looked so forward to a parcel arriving as much as this one. I sincerely hope I have no regrets…. And I have all fingers crossed.

This is going to be a labour of love and I can’t wait.

I will keep you updated.

Head over to the repair page here: Big Trak CE3962 restoration it was a pleasurable experience

Size isn’t everything… Apparently

Just a quick post, after having taken some time to think just how much electrical component’s have reduced in size in my lifetime.

What made you think this way? I hear you ask (or at least imagine that you ask.)

Well, today I had ten Audio amplifiers and fifty charging points delivered. Now, years ago I’d have probably had a large van deliver this little lot but today a small sized Jiffy bag came through my door containing all the above.

Ok the charging ports were micro usb ports and the audio amps were some small audio amps in an IC format needed for a current project I’m working on.

Amazing isn’t it just how far this technology has progressed. And shrunk in size.

My problem is that I’m easily impressed.

Impressive stuff.

Have a good day.

Technics Mash SL-XP165 Portable Cd Player With XBS Bass

The listing states:

For parts or not working, Does not power on don’t know what is wrong with it,screen looks to have a leak

EBay

This is probably going to be one of if not the least problematic units I have received yet. Probably more along the lines of boring for those looking for a repair report, I fear I have brought you here under false pretences, that was not my intention and I apologise if that has been the case.

Another unit from 1996 (therefore now 28 years old) this one originally had rechargeable batteries which were a bonus item for such a unit at the time. Personally I’m using good old alkaline batteries for test purposes, I doubt I will be using rechargeables.

I down loaded the instruction pamphlet, grabbed a pair of earphones and then dropped in two AA batteries and a CD.

Nothing. Silence…..

I looked at the unit, the seller is right I thought….then I pushed the play button and took the switch off hold on the side and put the second switch into normal operation and almost blew my ears off.

Superb sound and it was quite obvious that the unit was working. All buttons are doing what they should do, the Xbass system is phenomenal and the volume dial is faultless and crackle free.

It just goes to show the seller in this case wasn’t fully aware regarding how the unit works. You have to turn it on and off to get it working, it’s not all automated like other similar units. See video below.

Stop start works good

The unit is a bit tatty and the indicator panel has had some leak by the looks of it (See photo at top of this post) but even though this looks a bit poor cosmetically it does still display most of the information, it’s just not showing the track number info. Yes I could probably try another screen on this unit but what is the point? It works fine and the unit will gain no significant value for doing such a fix. It’s just not a financially viable choice unless I somehow come across a no value donor unit and seeing the prices people think these units are worth, I can’t see that happening anytime soon. And the Sony donors I have just aren’t compatible.

So I’ll leave it as it is. As the saying goes, “if it ain’t broke, don’t try to fix it.” It isn’t faulty, the only fault was in the sellers knowledge of its workings.

Another one saved from landfill. And that’s a positive.

Garden solar lights

I purchased a pack of 5 of these cheap old garden lights from a local garden centre. I know if you buy cheap you pay twice but these did look quite reasonable. I know that most people only expect a season out of these lights however I try to look after mine, bringing them in during winter months when the garden isn’t being used and sunlight is non cooperative.

These were so full of promise, worked lovely for a few days and then two of them just didn’t work at all.

I took them apart and decided to test the batteries, both were showing 0.6v so i suspected the charge circuit was not working. When I put in a fully charged AA battery the lights came on but when exposed to light they remained on, so in a way I am right but it might be slightly more complicated. The battery isn’t charging, also the switch off is not occurring when exposed to light.

I’ve done a few tests using the multimeter, the solar panel is ok and giving a reasonable voltage under sunlight of 2.4v.

The circuit board only consists of three components and two out of the three test ok. The issue seems to be with the YX8018 controller, the small four legged component in the pictures below.

What is a YX8018 controller?

YX8018 is a high-performance solar lawn
lamp boost control chip, which is suitable for a solar lawn lamp powered by a 1.2V rechargeable
battery in series.

The main functions include charging control, boost drive, optical control, etc.
The solar lawn lamp mainly uses the energy of
the solar cell to work. When the sunlight shines on the solar cell during the day, the light energy is transformed into electric energy and stored in the battery, and then the battery provides power for the LED (light emitting diode) of the lawn lamp at night.

It has the advantages of safety, energy saving,
convenience and environmental protection.It is
applicable to solar products powered by one 1.2V
rechargeable battery.

Conrad electronic SE

This appears to be the culprit after some basic tests have been carried out, there is about a 16% failure rate in these components so I don’t hold out a great deal of hope for the two that I’ve ordered. I shall eventually order a stack of them from China but for now I wanted some a bit quicker so I have ordered locally.

Well, the two components I ordered have arrived today. But now I need three, as in the week another one has suffered the same issue. On top of that I have dropped one of the units and the solar panel has parted company. I’m now sourcing some liquid solder that may assist with getting this problem sorted. As is normal with me this little project has escalated due to my utter clumsiness. I must do better in the future. (Sounds just like one of my old school reports.)

I dismantled the two units I previously mentioned and followed pretty much the same process with each. Desolder, remove component, wick solder, put new component in place and then put a semi charged battery back in.

I left the lights in the sun for a couple of hours and the charge has lifted from 0.8 to just over 1.1 volts so I’m happy that the charge circuit is now working.

The final test was to turn on and see what happens. Good news, nothing seen until I covered the solar panel and then the lights came on. Excellent, job done and more items saved from landfill. I must say I was really happy with my soldering on this job, it appears to be getting better.

Now working

I just need another component for that other one I broke in the week. However I won’t bother you with that one 😂

AIWA Personal Radio Cassette Player HS-TX406 assessment and repair

I recently purchased this item, you can read the original post here: AIWA Personal Radio Cassette Player HS-TX406

I love this little unit, it has a great radio reception probably better than a number of Sony Walkmans I have worked on to be honest. It has arrived in good cosmetic condition with only a few dinks and scratches commensurate with its 30 year plus age.

On opening up the unit it’s patently obvious that this is another drive belt issue, it’s saggy and breaks on removal. Luckily I have a replacement belt that I purchased earlier.

It’s another saggy worn belt issue

And that is basically it. No major dramas it’s as simple as replacing the belt.

A bit of light grease on the gears, a tweak of the speed adjustment and all sounds as it should.

I’ve used a calibration tape with a 3Khz sine wave, it’s tuned in pretty close to the tone and I’ve used a downloaded oscillator software package to check the matching. It’s not a professional setup but it’s fine for my requirements.

All working with a new belt

Sorry there is nothing else much to write but I have a good working unit that plays tapes well and all I can say is I’ve saved yet another easily repairable unit from landfill. I already have someone who wants to take this one off my hands so I hope it will have many more years of trouble free operation.

Jobs a good ‘un 👍

Sony Digital Radio Cassette Walkman WM FX-20 assessment and repair

I recently purchased this unit and you can find the purchase report in this blog post: Sony Digital Radio Cassette Walkman WM FX-20

The initial report of the purchase stated the issue was solely with the tape playback and that every else works fine. Cosmetically it looks fine apart from a bit of cleaning that is needed in the battery compartment, touch wood there isn’t any battery corrosion.

I’ve kind of jumped the gun a bit here in ordering a set of new drive belts for the unit, the fact it is 33 years old now probably means it would be money well spent. ( I may order a stock of belts for any future projects that I partake in) The belts alone were £6.95GBP so that now takes the total for this project to around £26.00GBP in total, but I’m going to use this personally so I’m not too concerned. In good condition and in full working order I could still make a small profit on this so at this stage I’m not too concerned.

The unit arrived on the 29th April. It is in a very good cosmetic state and all the lettering on the buttons is intact, a few small scratches and battle scars as expected but overall very good.

Radio and all button functions work fine, when you push any of the cassette buttons you can hear the motor run so no issues there. Let’s get this package dismantled.

Once inside the most obvious issue is that the belts have turned to mush.

I remove what’s left of the old belts, give a good clean to the cams and reinstall new belts that I have purchased earlier. A little bit of grease to the moving parts and cogs and all moving smoothly. As I’m doing this I notice a problem that I was not expecting, there seems to be a damaged cog, see the video below:

Damaged cog

Well, that’s a bummer as I’m going to have to obtain a donor for a new cog on the fast forwarding capstan, I’m hoping they are all pretty much standard so I will keep an eye out for a cheap option to repair. Whilst checking the system out it becomes apparent that this cog is specific to the fast forward operation so as long as I don’t use this then it should all be ok…shouldn’t it?

In theory yes, however every now and then when in play mode there is a slight dip in quality so I’m not going to chance damage to a tape.

Conclusion: it’s fixed, sort of. I’m looking for a donor cog that will fully fix the issue, the radio is fine, tapes can be played it’s just that I don’t really want to damage any until this issue is sorted. It’s a shame as it really was just those rotten belts that needed replacing. I’m pleased with what has been accomplished, yet again another 30+ year old electronic item has been saved from landfill. That’s a result.

Sony ICF-480L 3 band radio assessment and repair

I originally posted regarding the purchase of this item in this blog post Sony ICF-480L 3 band radio

The radio was received earlier today. Cosmetically it is a bit tatty, batteries were placed into it and apart from a quick flash from the power light when it was switched on there was no sign of life. So the original description was false as it stated that it powered up with a very low volume. Oh well, not to worry, it now gives us something else to look at.

Looking in the battery compartment there looks to be corrosion, this seems to be a common problem with items I’m buying at the moment. The screws have all been tampered with so I suspect others have been inside this radio prior to my purchase, this could be interesting to see what’s already been tampered with or attempted.

I’ve had the unit open and the first thing that comes to light is the utter filth inside. The speaker is thick with god knows what and the board and switches are also covered in the same filth. Before I do anything I’m going to get this cleaned up.

I’ve used IPA on the board and cover and on the (thankfully small) corrosion on the positive battery pole and this has cleaned up nice. I’ve used contact cleaner on all the switches and dials and these have also come up ok.

The speaker grill, I have tidied up and used permanent marker to get rid of the marks on this item. This has tidied it up really nicely.

On the speaker I just used a dry cotton bud to wipe it over but I have my suspicions with this speaker, it looks quite worn and earlier reports on the lack and consistency of sound points to this being a potential issue with this unit. There are no clicks and pops when turning the unit on, there is a power and tuning light. Just no sound.

The speaker is a 4 ohm 1w speaker, I’ve used a multimeter to check its operation and it’s showing as dead, not registering at all, it should be looking at indicating something within its 4 ohm range. I’ve double checked it by putting a battery across the terminals and there are no pops or clicks so this confirms things. I now need to source a new speaker.

Trying to source this speaker in the uk is a tad problematic. There are items available but I’m not paying out two to three times the value of the whole unit. I’m going to try some thrift shops to see if there are any suitable donor units available if not I’ll have to purchase a few of them from China, and that will still be cheaper than purchasing here in the UK, crazy isn’t it? But it’s a long wait….

I did manage to get one from the Uk. Paid about £5.18GBP and it should be here in a couple of days. The annoying thing is that the postage is almost the same cost as the actual speaker and that only cost £2.69GBP. Annoying though that is, it has to be done if we want to get this fixed.

I couldn’t get a 1w 4 ohm speaker only a 1w 8 ohm speaker, this will be fine as at this level of use it will not affect output at all.

A small bit of desoldering, removal of the speaker clamp and the speaker comes away after a little persuasion. I take the opportunity to clean the board and all the battery contacts with some cleaner, and all corrosion marks and debris are now a thing of the past.

I put some contact adhesive on the speaker grill and put the new speaker in place, clamp is attached and I now solder the speaker wires back in place.

All screws back in place, new batteries in the rear and battery hat hatch closed, the unit looks good.

But does it work?

Radio works – have a listen

You betcha! Have a listen to the short video above to hear it as it should be.

I’m very pleased with this little project. Simple repair in the end but in my eyes it’s another item that isn’t going to landfill. And that’s a win for me, as it’s a nice little radio and I’m going to get some good use out of this.

Jobs a good ‘un 👍

AIWA Personal Radio Cassette Player HS-TX406

Just purchased this item, here is what the listing said:

Radio works fine but the cassette is poor at playing tapes as the sound quality is really slow.
EBay

Yet another Cassette player circa 1990. Again possibly another one that needs its drive belt renewing, so in that case I’ll order one in. This one cost the grand total of £9.95GBP.

This link takes you to Radio museum.org where you see the technical detail of this unit : Aiwa HS-TX406

See the assessment and repair of the unit here: AIWA Personal Radio Cassette Player HS-TX406 assessment and repair

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What is a YX8018 controller?

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