Racal IR772 PIR - full examination 

Back in my early days at Modern Alarms / Group4, I seem to remember seeing a "technical bulletin" regarding this detector and how it had a "bug" that caused the device to go into "alarm" at a preset time interval, thereby causing false alarms ? Hence why we only used them for a short period of time before moving onto a different model/brand. Keep up the brilliant video's, so interesting and a delight to watch and remembering the "good old days" of being an "alarm engineer".

I love those animations and simple but detailed explanations in this It makes it so easy to understand and interesting

Beautifully done Matt, as usual.

I absolutely loved the video! Well done!

Love it! All your videos are always well edited and detailed

When we moved into our house we had the MK 1 versions of these, one in the back room, and one in the lounge. I don't know how old they were as I don't know the dates the MK 1 version was manufactured, but I presume pre 1983 if thats when the MK 2 came out. I know they were MK 1 as they had the dark lense cover on show, similar to the Gemini P.I.R. detector. When I was little I used to love setting the system and seeing how far I could creep slowly past the detectors before they alarmed, and if I was slow enough I could do it! I did fail on multiple occasions though and I remember annoying my mother with how much I was setting the alarm off! I must of been a very patient child as I could spend up to 10 minutes just trying to creep past one detector! I don't remember them being as undersensitive as you say though- at least ours would activate with 2 steps most of the time, I remember them being sensitive enough thats for sure. We never had any bother with the tamper either. They eventually got ripped out in 2010/11 when the house was partially rewired and my parents chose to opt for a wireless system (biggest mistake ever, I have got them back on wired now don't worry!) But I can honestly say, in the whole time they were installed right from 1980 something all the way until they were ripped out 12 or 13 years back, we never ever had one false alarm. I think probably for a combination of reasons, two being the reliability (in our case anyway) and the fact they were my childhood detectors, these are my all time favourite P.I.Rs ever. I have got 3 new old stock ones, and when I move out you bet I will be fitting them in my own home! Such a shame the racall guardall name is gone.

The tamperswitch is a typical card edge connector, very sensitive to dirt and corrosion. It looks like the designers had to cut cost somewhere and decided to do it there. Just like old game cartridges you need a lot of Isopropanol Alcohol to clean these contacts. They seem sensitive to oxidation. Cotton swaps drenched in alcohol work quite well here.

Had these installed in my previous house for twenty years, and never had a problem with the tamper circuit contacts, also if I recall ours had a slightly different base fitting for mounting the sensor unit in the corner of the room.

I have a ton of PIR sensors cheap and a few pro-emd (and a few FLIR devies too) but I'm replacing most with some of the microwave motion sensors that are ridiculously cheap. Also picked up a few outdoor and indoor motion sensing lights. The indoor do an absolutely amazing job of sensing me through walls and before I'm even in a room,, literally through walls. "Farpoint 7500 Lumens" at my grocery store for $20 but they seem to sell under different names.

The 771 was one of 5he first PIR, before the 771 we only had the option of Ultrasonic or microwave, compare the size of the 771 with an Ultrasonic detector the tamper problem was only occasionally, we are taking about early to middle of the 1980, a lot if 5he panels at the time involved relays and key switches, the PIR of choice after the Racal 771 was the Cerberus IR 6

WOW! Awesome Video, I now have a full set of these, the MK1 which has a Proper tamper switch, and a blue circuit board, the MK2 which is the same as yours, and the MK3(I think) which has an extension board on top to help with the wiring resistance. These are my favourite Detectors, I love the look of them installed. Keep Up the great alarm videos 😁

should do more of these videos, love the lift videos of coarse but always had a thing for older security equipment. shame can't get ahold of anything that old around in the us. miss the older retro stuff. I got a big ass ultrasonic from the 1970's but thats about it as far as older stuff.

Ive got one ofnthese but it has a dark cover over the detector. Yours if you want it ?

I love those old PIRs you have, hard to come by now. Great demonstration with the led showing detection zones, I still think that's a really good way to show it. Are you still servicing alarms for a job?

Very interesting tear down of a PIR. What is the purpose of the white cover on the PIR?

Brilliant video. This sensor is very interesting how it works

Does anyone remember the racal 738 I believe they were the predecessor to the 772. Modern alarms used to use them and used to make a loud click when you walked by

love the alarm videos

Hey how can I buy your merchandise pls

Always interesting to see how one of these works. There’s a PIR installed in my living room and I love to mess around with it. The alarm system it’s connected to isn’t armed though so it’s not like I’m really triggering much. It does turn on a little light in my parents room though. (Which I believe is a ceiling mounted sensor/alarm status monitor)

I have one now

More like this mrmatt 😀

Make a vídeo of cs8 sirens again Because i want to se If the sirens are in ther location. And make a siren test video

I can't stand devices that have the "jumper" style tamper switch. You'll be up on a ladder and accidentally drop the cover, causing whatever the jumper is to become ejected from the cover upon impact, and nearly impossible to find.

Moorreee pls!

If you have the "Instructions" it tells you that the 772 is a DUEL element sensor. (It's predecessor, the 771 was only single element.) You are right about the configuration of the tamper connections, but I never had any trouble with them going into tamper. I do think you are being a bit "unfair" because the 772 was one of the first PIR's available, so yes it did have a limited view, yes it had no anti-creep, but it was good for its time. If the PIR was secured to a wall, no coin is needed to remove the front cover, you grab it by the sides (one hand) and gently pull. The MK2 did have one advantage over the MK1, it had a white window, the MK1 had a dark window, the reason was to prevent white light (car head lights) setting it off, but then it should not be mounted looking at a window. The "back plate" was originally an optional extra, it also angles the PIR down by 5 degrees. Keep up the good work.

Radio Shack sold these under a different name Safe House and weren't to bad for the day. I used this inside my car and with windows open it didn't false with its low sensitivity.

13th