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Old 21st Oct 2019, 7:40 pm   #21
Restoration73
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Default Re: CB spares

It is common anode. My one is the same but marked TR3210L:

If you inspect the pcb you will see pins 4 & 5 are linked (Vcc) connect to +5V. Connect
a resistor say 1k in series with 0V (negative) and touch the free end to each segment in
turn and they should light.
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Old 21st Oct 2019, 7:43 pm   #22
SiriusHardware
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Default Re: CB spares

Yes, I got a similarly chatty reply from him, he was very helpful and added the extra detail at my request. I have a couple of the red DP-less ones on the way to me.

If only green would do, then I imagine it would not be impossible to fit a more modern display and reroute the segment signals from the channel switch to the right pins on the new display, because you seemed to say that the original green display you bought does physically fit. Of course an exact drop-in replacement is always to be preferred, if available.

Your picture of the very similar original green one gives me some hope that these red ones will at least be pin-compatible.

I would leave the green one stolen from the Harvard in the Rotel, where the green channel display is very much part of their signature 'look', and put a red one in the Harvard.

Edit: If you'll recall, the service manual entry for the same part in the similar Cybernet 3000 described it as 'Common-A' - common anode. If you have a DMM with a 'diode test' feature they can often light LEDs dimly just by themselves, so that can be another quick way to find out whether a display is common anode or common cathode.

Last edited by SiriusHardware; 21st Oct 2019 at 7:50 pm.
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Old 24th Oct 2019, 9:27 pm   #23
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Default Re: CB spares

The displays arrived today. I was about to set about metering out the pinout and then it dawned on me: Which way is 'up'? If a 7-segment display has decimal points then you can always be sure that the display should be oriented with the point(s) at the bottom. No decimal point on these, so...(?)

Nothing for it but to take one of my Cybernets apart: The first image shows what a good match these TR321OFs are for size. The number of pins / pin spacing is also the same. Hopefully you can also see in that image that there is an orientation mark, an indentation, in the centre of the lower edge of both displays. This is also just about visible in the second image of the TR321OF display only.

Third image: The pinout of the TR321OF display seen from the rear with the orientation mark downwards. The two centre bottom pins are the common anodes - in the radio these two pins are connected together. I've only shown the front view of one of the two characters on the display. The references such as 'a(L)' and 'a(R)' mean 'Segment a, left character' and 'Segment a, right character' and so on.

I didn't go so far as to swap one of the displays into the radio but I did 'buzz out' the pinout of the radio's display and it is exactly the same. Based on this, I'm prepared to say that these TR321OF displays should be a drop in replacement for a RED Cybernet channel display in a typical 'standard sized' Cybernet radio.

(Bear in mind of course that the smaller Cybernets such as the Cybernet 1000 / 2000 used a smaller display).
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Old 24th Oct 2019, 10:16 pm   #24
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Default Re: CB spares

Thats useful to know.
Thanks
Mike
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Old 28th Oct 2019, 8:18 pm   #25
Richard Witney
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Default Re: CB spares

I have found a red LED display from a CB see photo. Any use to you?
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Old 28th Oct 2019, 11:54 pm   #26
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Default Re: CB spares

Hi Richard
I have bought some of the red LED's from ebay. but thanks for the offer.
Something I forgot to realise is the red LED' has to shine through a green lens fitted to the front panel, so it is a kind of dim channel display now. But at least it is working again.

Mike
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Old 29th Oct 2019, 12:17 am   #27
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Default Re: CB spares

Crackle, can I just ask you: At the beginning of this thread you said you had bought and tried a green dual 7-segment display but that it had not worked. To what extent did you try it?

Were you actually able to physically fit the green display in place of the original display? I'm just wondering, in view of the green filter / red filter problem, whether it would be worth working out how to rewire the display PCB for use with currently available green displays like the one you originally bought.

I would imagine that the common dual displays (those with decimal points) have two additonal pins for segment 'h', which is the decimal point of course. They probably still have separate common anodes.
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Old 29th Oct 2019, 12:54 am   #28
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Default Re: CB spares

I've just gone looking for a 'typical' modern green dual display with a view to working out how it could be modified to fit in place of a Cybernet display, and I came across this Kingbright twin green seven segment display on Farnell.

http://www.farnell.com/datasheets/1718637.pdf

What's odd about this is that it is depicted as having decimal points but it only has 2 * 8 pins on a 0.1" / 2.54mm matrix like the Cybernet display, and, although it is drawn in a different way the pinout is exactly the same as the Cybernet display. The characters are 10mm high (same as the original Cybernet display).

The outside dimensions of the Kingbright display are very slightly smaller so it will fit inside the chassis cutout through which the original display usually pokes.

What I don't get is how / where the connections to the decimal points are to be found, but if it does not really have decimal points, so much the better.

I may order one of these through work and sound it out as a possible green replacement.

Edit: Argghh! Just noticed - 'No Longer Manufactured'.

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Old 29th Oct 2019, 1:03 am   #29
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Default Re: CB spares

..RS claim they will be getting some more stock in. Sold in fives, but not too bad a price.

https://uk.rs-online.com/web/p/led-displays/8770867
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Old 29th Oct 2019, 8:25 am   #30
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Default Re: CB spares

Hi
I tried the green LED I originally bought first one way with the dots down and then the other with the dots up. When it was reversed only 2 segments worked. see image in post #3 (which I showed upside down) I seem to remember that when I tested it after your post #23 that I determined it was a common cathode.
It may be that another similar LED of the correct type, common anode, would have worked.
The LED was sold as suitable for Cybernet radios and I got a full refund, I had stated on the order it was for a Rotel RVC240 type. It is quite possible that it would work in the modern Cybernet radios.
I dont fancy rewiring the PCB at all to work with a common cathode display.

So it looks like the dot on those displays is superfluous then.

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Old 29th Oct 2019, 10:54 am   #31
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Default Re: CB spares

I've ordered five from RS through work as I have at least one Cybernet with a green display (Rotel) and I would like a spare myself, since your case has demonstrated that they can fail.

If / when they do arrive I'll check that they are pinout-compatible with the Cybernet displays and if they are I'll forward one to you. (They aren't costing me anything).

Let's just hope that RS really do have some incoming.
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Old 29th Oct 2019, 11:30 am   #32
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Default Re: CB spares

OK thanks that's very kind.
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Old 29th Oct 2019, 6:24 pm   #33
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Hmm, well, bad news and maybe better news. RS have admitted that they won't actually be getting any more because they are no longer manufactured.

Better news, Mouser UK appear to have actual stock

https://www.mouser.co.uk/ProductDeta...fu%2FVL1AJXw==

...although I notice their re-order quantity is zero, so once they are gone they will be gone. I've ordered a small number and we'll see if they actually turn up.
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Old 31st Oct 2019, 3:30 pm   #34
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Default Re: CB spares

Would be interested in whether the Mouser sourced ones work since I've a couple of Green-eyed 134 chassis & while they work for now (iffy centre segment on the nicest rig though, typically!) it'd be good to have a few spare in stock for future...
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Old 31st Oct 2019, 8:17 pm   #35
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Default Re: CB spares

The green displays arrived from Mouser today, so yes, they do really have them.

I've now had a chance to have a look at them and compare them with the red ebay display which has been established as having the right characteristics - size, pinout, etc, to drop straight into a standard sized late seventies / early eighties Cybernet.

Regarding the green Kingbright display from Mouser:-

The package is exactly the same height and fractionally less wide - this is only because the red ebay display overhangs a little bit more at the ends. The character height and width are the same.

It has 16 (2 * 8) pins in the same layout and with the same pin spacing as the red ebay display.

This display DOES have decimal points but they are inert / not connected to any of the pins.

The pinout is exactly the same as the red ebay display, as per image #3 in post 23 of this thread. Correct orientation of the display is given by the position of the decimal points rather than by an index mark.

Like most conventional green seven segment displays the face of the display is mid-grey - that should disappear behind a green filter, but if you have steady hands you could always carefully paint the display face matt black.
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Old 31st Oct 2019, 11:29 pm   #36
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Default Re: CB spares

Thats a useful bit of research, thanks now we know what type to use for these old CB's.

thanks
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Old 1st Nov 2019, 7:16 pm   #37
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I've sent one of these green displays off to Crackle.

One thing which occurs to me is that it might be prudent to try to get the face of the display as close to the front panel filter / lens / window as possible. If there is any significant gap between the display and the filter / window then some of the light from the segments will reflect back off the inside surface of the filter /window and illuminate the grey face of the display.

I'm only speculating, but this (hypothetical) effect could be minimised by making sure there is zero gap between the display and the filter.
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Old 4th Nov 2019, 5:46 pm   #38
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Default Re: CB spares

That's much better now, the new LED kindly sent to me by siriushardware fitted like a dream, and looks the part.
I did move the LED forward as much as I dared, but I dont think there was much internal reflection off the green lens.
Thanks very much

Mike
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Old 4th Nov 2019, 5:57 pm   #39
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Wow, that was quick - thanks for trying it out so quickly.

So we can now say that those specific Kingbright displays are suitable replacements for green units, BUT they are already discontinued by the manufacturer at the time of my writing this, so anyone else who might need one, get them while you still can.
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Old 4th Nov 2019, 11:44 pm   #40
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Default Re: CB spares

Better add the exact part number of the green Kingbright display in case all of the links in this thread eventually go dead.

Kingbright Part Number: DA04-11CGKWA

I believe the 'A' in 'DA04' signifies 'Common Anode' and the 'G' in '11CGKWA' means 'Green'. The '04-11' portion may mean 0.4" / 11mm (character height).
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