What might this circuit be?

[Trevor Rymell]

This is a bit of a stupid question I realise, but would anyone care to speculate as to what this circuit could be for? I'm not really expecting anyone to be able to identify it but you never know. It's just possible someone might have an idea.

I found it in a small sports field in the compound of a hospital so I think it might be part of some discarded medical equipment. The top cover was missing which might have had a descriptive label. The whole interior of the box was encapsulated with a soft, black rubbery material that was very easy to dig out to reveal the PCB. It's a pity that there are no legible numbers on the ICs which might also have helped. On the PCB itself but buried under the encapsulation, are a 5-pin and a 2-pin header. Inputs for a programmable IC possibly. There is only a single 3-pin connector accessible from the outside which has a black, red and white cable connected to the PCB. I assume two of these (black/red?) would be the DC supply but I wonder what could all that circuitry be doing that requires a single output wire. The solid alloy box and encapsulation suggest water-proofing and high vibration protection. Anyway, I thought I'd ask on the off chance someone might have an idea. The alloy box will come in very handy for a mast-head antenna amplifier that needs a neat, waterproof housing.
Trevor

 

[JimB]

I have no idea, but...

Try connecting some power, the red and black wires are power according to the legends on the PCB, then try probing around with a 'scope and see what happens.

It occurs to me that the arrow in the circle is trying to say "This way Up".

The alloy box will come in very handy for a mast-head antenna amplifier that needs a neat, waterproof housing.

Yes, nice box, all you need now is a suitable lid and a sealing gasket!

JimB

 

[Buk]

Looks like a serial (rs232?) comms board. Perhaps a data logger of some kind.

 

[Musicmanager]

It's the part that makes the thing,
that drills the hole,
that holds the spring,
that drives the rod,
that turns the knob,
that works the thing-ummy-bob !

MM

 

[Buk]

It's the part that makes the thing,
that drills the hole,
that holds the spring,
that drives the rod,
that turns the knob,
that works the thing-ummy-bob !

MM

Ah yes. A much better suggestion.

 

[unclejed613]

it's a radio of some kind, the TNC connector is a clue... also the unused pins marked TX and RX. A1 and A2 are likely antenna connections

 

[Nigel Goodwin]

it's a radio of some kind, the TNC connector is a clue... also the unused pins marked TX and RX. A1 and A2 are likely antenna connections

I would have thought A1 and A2 are address lines, probably for setting the address of the unit?.

But regardless, it looks to be a micro-controller device, and could be pretty well anything - not much use other than as a nice box.

 

[KeepItSimpleStupid]

What about a "dongle" of some sort. A1 and A2 set an address.

 

[rjenkinsgb]

Could L13 be an eight pin L272? - do the A1 and A2 pins connect to pins 1 & 3 on that IC, with power and ground to 2 & 4?

https://www.st.com/resource/en/datasheet/l272.pdf

If so, I think it may be a DC motor controller of some sort; A1 and A2 being armature terminals?
(Board label DCS V2.0 could fit with that, DC Speed).

 

[JimB]

it's a radio of some kind, the TNC connector is a clue

Please show us where the TNC connector is located.
Or is it cunningly disguised as a cable gland?

JimB

 

[Trevor Rymell]

[/QUOTE]

it's a radio of some kind, the TNC connector is a clue... also the unused pins marked TX and RX. A1 and A2 are likely antenna connections

I can't see a TNC connector - only the 3-pin socket with the red, black and white wires to the PCB. I also noticed the "RX" and "TX" legends which usually stand for Transmit and Receive but there's nowhere to connect an external antenna to.

My bet is it's a top-secret component from a Chinese spy satellite that exploded in space. I'm waiting for a knock on the door anytime from undercover NSA agents asking for it.
Trevor

 

[throbscottle]

Everyone thought that 3 pin connector is a TNC because we can't see the pins.
First thing I thought when I saw TX and RX was serial data connections.
I'd be inclined to give the chips a rub with some acetone - see if any writing will appear. Or perhaps a genie will appear and grant you wishes!
I reckon it's a faulty thing that's been replaced by tradesman on the outside of the building and s/he dropped it by accident.

 

[Ylli]

Getting back to the original question, this is not a "circuit", this is a "populated circuit board".

 

[Trevor Rymell]

Getting back to the original question, this is not a "circuit", this is a "populated circuit board".

I stand corrected.

 

[Ylli]

I stand corrected.

Whoops, I see I forgot the smiley. Just meant in jest.