New Project LED Bulova Accutron advertising clock

[Adam]

It started off as just a project, but due to some poor packaging, its now a project of a project. The screen was not, when I bought it, damaged. I thought it was such a rarity and would look cool above my workbench I decided to take the partial refund.

Well as you can see it kind of works. The time does increment so im just missing digits. The led unit is made by Kendale. There is a knob on the side inside the box to adjust time. Has anyone worked anyone of these before that can give me some possible tips?

If anyone is interested I'll post some more photos of the back and insides

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[Kasper]

Always interested Adam. Just layout the plastic parts on a new thin background and glue it together.

[Adam]

Its not the plastic i'm worried about. Its my missing segments. Its running OK, a bit slow but Im hoping there is a trimmer inside.

[charger105]

Hi Adam.
Yes, some shots of the inside would be interesting.
I guess it's either a driver IC, the display itself or bad solder joints. I had similar issues with my Vibrograf display, which was relatively simple to fix.

Is the display one discreet unit, or separate digits ?
Rgds.

[bruce wegmann]

I don't think this is a multiplexed display. The second digit from the left HAS to be a zero, but has a missing segment, but the zero on the far right is complete. Unless there are individually failed segments going on, there must be segment-specific driver transistors (which should be easy to locate, and replace), or a driver IC.

[Old Tom]

The clock may be running slow because it was intended for USA 60Hz rather than UK 50Hz (the clock frequency being derived from the mains frequency rather than a crystal which is normal practice for these larger LED clocks)- does it have a socket mounted transformer or an internal one? A four digit clock is almost certainly uses a direct drive from the main timekeeping IC without any external transistors/ dirver ICs. Missing segments as in the photos means the chip has suffered the dreaded "channel death" from being without power for too long. The chip may be replaceable but the cost is likely to be prohibitive for one of the late 1970s clock chips- much cheaper to buy a whole new (almost identical) LED clock module from China!

[Adam]

Sounds disappointing. Here are some inside shots. Im using an external transformer at the moment it looks to be 50hz

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[Old Tom]

Strange question but.... is this an LED clock or a mechanical drum clock that simulates an LED display (like some Sanyo Digiglo clocks). THere seems to be a background glow behind the non working segments which you wouldn't normally get with a LED display.

[Adam]

Its an LED im pretty sure. I'll take it apart tomorrow and post some more shots

[Adam]

More photos, Inside the box! Wasn't expecting that. Is this what you meant Tom? It is a mechanical movement of sorts. Are they just bulbs?

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[dutchsiberia]

Nice surprise! So it's a mechanical problem? Some bulbs are burnt out? And you'll have to figure out how to solve the 50/60Hz problem. (other synchronous motor, maybe from a clock radio, or different gear ratio)

[Adam]

I have removed one of the dead bulbs and need some replacements. Can anyone tell me what they are and where I can get them in the UK? I've not seen them before.


Also anyone got any ideas how to get the clock to 60Hz from 50Hz or if I can get a US to UK transformer to do the job?

many thanks


Adam

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[Kasper]

how big is that bulb?

I just had one in my hand yesterday...just 1 cm high. Coming from an old philips car radio from the beginning of the 80ties. One i wanted to restore. I changed it with a old christmas light bulb.

[Adam]

Approximately 9mm in length Kasper

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[Diginut]

I have removed one of the dead bulbs and need some replacements. Can anyone tell me what they are and where I can get them in the UK? I've not seen them before.

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Those look like 'Pea Bulb's or 'Dolls house' bulbs. They can be 6v or 12v as far as I recall.


http://www.ebay.co.uk/itm/Dolls-House-L ... XQlgtSo4q-

Hope this helps. Looking forward to seeing it working again !


.

[Adam]

I also found these, but what do I chose? There's no information on the bulb itself, will the just shine at different brightnesses? If thats the case should I replace them all?

Again any info greatly appreciated.

http://www.ebay.co.uk/itm/Sub-miniature ... IOdsQknGDA

[Diginut]

I also found these, but what do I chose? There's no information on the bulb itself, will the just shine at different brightnesses? If thats the case should I replace them all?

Again any info greatly appreciated.

http://www.ebay.co.uk/itm/Sub-miniature ... IOdsQknGDA

.

If you've got a multimeter just measure the voltage either side of a bulb, working or not. I don't know the mechanism within the Bulova, and it shouldn't matter if the supply to the bulb is AC or DC, but your multimeter setting will reveal whats driving them.

You can then choose 6v,12v,14v,18v,24v ... They will draw their rated current at their rated voltage.

You could also snip one lead of a working bulb and use the multimeter to measure current going through it.

However, once you know the voltage I would think its best to replace the lot, to get uniform brightness.


.

[dutchsiberia]

I got the microlamps I needed for a vintage clock radio a while ago from conrad electronics. In your case, www.conrad.de :)
Getting the clock to work at 50Hz might be difficult. You need to convert 50hz to 60hz (might be costly) or get a replacement synchronous motor (difficult to find a vintage fitting part but most elegant solution I think) I see a lot of little motors on Ebay. ("AC synchronous motor") Motor doesn't need to be vintage of course, you just need the correct rpm and a way to correctly connect the motor to the clock. The gear on the motor is crimped in the axle if you're lucky (just brainstorming) Then you can get a correct 230volt 50hz motor and use the gear from the old motor.

My vintage Sony flip clock clockradio has a 50/60Hz switch that changes the gear ratio.

[Adam]

Well some of the way there.

Stabilised the front screen with a perspex backing. Its OK and with some more tlc I can get it look pretty good


Changed the damaged bulbs with a relly good match(after a few attempts). The bright bulb on the second digit is original. I even got a colon divider back, that was a nightmare as it was on the other side of the board and I had to dismantle everything.


I havent managed to fix the main light. I've replaced the bulb and the starter box. Other than that I dont really know what else to do.


And of course getting it to 60kw from 50kw, thats where i'm really lost. Im already using a US to UK transformer(is this necessary?)

Maybe one for the electrical experts.

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[bucko170]

It's looking good, and a little more TLC to disguise the crack on the front will have it looking even better.

What size is it? Can you take a photo of it next to a can of lager - I find that is the best way to gauge the size of something in a photo.

[Diginut]

And of course getting it to 60Hz from 50Hz, thats where i'm really lost. Im already using a US to UK transformer(is this necessary?)
Maybe one for the electrical experts.

Adam - there is a simple'ish solution to the 50hz / 60hz problem ...

Basically, use ebay.com to buy a car cigarette lighter adapter *from the USA*. $15-$20.

These plug into 12v DC in your car, and generate 110v AC at 60hz …

Off course, you'd need to feed the 12DC from somewhere else like a UK 240-->12dc DC but you only need a mere 10 watts, but this would solve the 60hz problem

[Adam]

Its only the crack on the top right thats really noticeable. There are a few more that have sealed up well. I have taken a couple of quick photos for scale.

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