Re: Autona 2250 circuit

[Terry Pinnell <terrypingm@xxxxxxxxxxxxxxx>]

Bill <Nomailorspam@xxxxxxxxx> wrote:

>In article <4sprr7p21otpif9hr4l127gioirtbg7aja@xxxxxxx>,
>terrypingm@xxxxxxxxxxxxxxx says...
>>
>> Hi, first post here.
>>
>> Anyone know possible source of the circuit diagram for my 15 year old
>> control unit please? It's an Autona Series 200, model 2250. Web searches
>> for Autona Limited, Princess Risborough, lead to an unrecognised phone
>> number. This morning I'll try Chiltern Electronics who are in the same
>> location, but I'm not too hopeful.
>>
>> The re-entry delay on mine has failed. Probably down to my impatience. I
>> removed the front door reed relay sensor door because it had become
>> unreliable, often 'sticking' in its passive state instead of triggering
>> the alarm re-entry delay warning. After the replacement the re-entry delay
>> has failed. Instead of a 30 second warning while I disarm it with my code,
>> the siren sounds immediately.
>>
>> I think I must have damaged that section of circuitry while soldering in
>> the reed. I did check that the passive voltages were zero, but that's the
>> only cause I can think of.
>>
>> So I might dust off my shed workshop bench and try making an add-on to
>> provide this lost functionality. Access to the circuit diagram would be a
>> great help.
>>
>> There's one other longshot approach I'm trying in parallel. By removing 4
>> screws I was able to get a good look at the circuit board. Its main active
>> component is a PIC16FC4. I know virtually nothing about PICs, but just in
>> case that *has* become faulty I thought it worth dropping in a
>> replacement. I couldn't find that specific one in stock anywhere so I've
>> taken a gamble and ordered a PIC16C54-XTI/P  (8BIT CMOS MCU, 16C54, DIP18)
>> at £3.64 from CPC.
>
>A PIC chip is a computer chip with custom "programming" loaded into it.
>Also called a "microcontroller".
>
>Your replacement of that chip would be like replacing your fully
>functioning desktop computer with a new computer which DOES NOT HAVE ANY
>SOFTWARE ON IT! It is not going to work.
>
>Don't mess with the control unit.
>
>The problem is what you have changed and that is the door. It probably
>had an "end of line resistor" connected to the switch in the door. The
>new switch needs one as well.
>
>If you no longer have the old door and the old switch, I suggest you
>call an alarm company and have them come out and fix the door switch.
>They would know or would be able to figure out what value resistor
>should be wired into the circuit.
>

Thanks Bill.

Yes, that was dumb. I realised my mistake shortly after getting CPC's
order confirmation yesterday!

And that wasn't the only dumb thing I did. Part way through breadboarding
my proposed add-in, I needed to test a few voltages and resistances at the
CU connections. (Because the circuit would have to be more complex than I
described, to maintain the EXIT delay.) In the course of doing that I
discovered the cause of the problem: I'd swapped the anti-tamper loop and
delay loop!

So, much wasted time but a happy ending ;-)

--
Terry, East Grinstead, UK