TinkerBear

It's now been 113 hours without a peep since I reset the wireless module and power-cycled the panel. (At risk of jinxing it:) I think it's fixed! Thanks to everyone for taking the time to make helpful suggestions! I've been banging my head on my desk for a month now. Just explaining the problem to someone who would know what I was talking about was amazingly helpful. I was thinking this was akin to rubber duck debugging, but as none of you are made of rubber, this is more accurately known as "confessional programming". I'm so happy I don't have to throw more money at this thing.

Yea, that's a good idea - which absolutely didn't occur to me. I'm still waiting to see if it recurs after I reset the wireless receiver a couple days back - I'm at 43.5 hours since a complete power cycle and nothing has happened, which... doesn't necessarily mean anything yet.

Yep, I swapped other boards into the positions and addresses of zone expanders 1 and 2 at first, thinking I'd just gotten some broken bits off eBay and it would be a simple fix. But the failure persisted on zones 9-21. Then I swapped addresses without moving the boards around - to try to rule out interference from the power transformer inside the case - and still zones 9-21 failed. I'm currently waiting for a recurrence (or lack of one) after resetting the wireless receiver buried in the RFK5500 keypad.

<whinge> Ok, so you're going to make me do my sums again.</whinge> Using the numbers from the PC1864 install manual... Main PCB @ 110mA (but this isn't on the Aux output, it provides it) 2x RFK5500 @ 135mA 4x PC5108 @ 30mA 3x Swan Quad PIRs @ 10mA (so far) 1x Eyezon Envisalink 4 @ 65mA Totals to: 485mA on the Aux output, which is limited to 500mA. Closer than I expected, but within spec. Except... is the keybus power considered part of Aux or not? The install manual isn't clear. It doesn't mention a separate current limit for the keybus, so probably. Currently, the zones that fail are assigned to expanders inside the cabinet, so they're less than 30cm of wire from the PCB. I'm measuring 13.62v at the panel, 13.60v at the expander boards. I've swapped boards and addresses a number of times now. (Wasn't keeping good track of troubleshooting steps at first.) The problem has always manifested with zones 9 to 21, regardless of what zone expanders are assigned to handle them. Now I'm thinking if the problem continues to recur, I should try with no expansion boards assigned to those zones. That hadn't occurred to me before now.

I'm starting to suspect the RFK5500 keypad. The "RFK" version is a combined PK5500 keypad plus a PC5132 wireless receiver on the same PCB, but I believe they still operate independently. I'd reset the alarm panel and the keypad, but I hadn't reset the wireless receiver. I'm not sure how the wireless functions work -- if the wireless zones are reported to the panel the same as zone expander events are -- but if they were, it would explain what I'm seeing. I've now done a [996] wireless module factory default, and... now the "PC5132" has disappeared from the module inventory [903]. I guess it needs to be set up again to appear? Now it'll just be a couple days to a week to see if the problem recurs.

Well, the alarm panel is meant to power every other item in the system. I've done the power budget, and I'm nowhere near maximum. The panel is in the same room as my workbench, so I've got a keypad and some of the zone expanders on my bench. The zones that fail are unfortunately in the box on the wall. I could change the addressing to put those zones on the ones on my bench... but I'm not sure what to look for. I get a protocol capture wherever the bits are - and those zones are reporting open.

Battery is a little old - 2019 - but the voltages look fine. I don't currently have a way to track the voltage for the multiple days it takes for a failure to happen. I guess I could bodge together something with an Arduino... but that's probably a last resort? As far as power to the house - we do get frequent power failures here, so we have solar plus battery backup. There is a small gap if power fails, but I get multiple notifications if that happens, and it hasn't happened when the alarm freaks out.

Using four-conductor tinned alarm wire, no shielding, two short runs 5m each. I've looked at the signals with an oscilloscope, and it looks pretty clean to me.

I'm trying to install a DSC PC1864 panel with 32 zones in my house as part of a renovation. I'm putting sensors on doors + windows + motion, which is probably overkill, but I'm retired so it's partly about keeping myself occupied. As the entire DSC Power Series is discontinued and out-of-stock, I got one used off eBay with 4 PC5108 zone expander boards (40 zones). (Both alarm panel and RFK5500 keypads have been reset to factory defaults, several times.) The install is progressing (slowly) along with the renovation - I've got 6 zones connected right now, the wire/sensors going in as the contractor tears apart the walls for window replacements and insulation. Just for testing, I've connected all 4 zone expanders and wired each zone with a single 5K6 resistor, and enabled as zone type 03. I can test each zone individually by shorting with tweezers or disconnecting the resistor, and the panel responds. (I've now got the door chime enabled for all the zones with dummy resistors, just to make testing easier.) Here is where things start to get weird... Zones 9-21 will (at some point after a day or two) spontaneously report that they are open. All of them at once, when they have resistors solidly connected to them. That's all of zone expander 1 and part of zone expander 2. The zones remain open until the panel is power-cycled, or the zone is physically shorted or opened. My first theory was that some of my zone expanders were broken or marginal, so I swapped their addresses around to verify. The problem recurred... still on zones 9-21, even with those zones on different zone expander boards. This suggests that the zone expander boards aren't at fault. My second theory was that the alarm's main board has some kind of memory fault, and the zone failure was happening within the main board, not coming from the zone expanders. I installed a KeyBus protocol dumper ( https://github.com/taligentx/dscKeybusInterface ) on a microcontroller and logged the protocol exchange. The bogus zone openings are definitely coming from the zone expander boards, and not simply being imagined by the alarm panel. My third try... was to throw money at it. I ordered and installed an Eyezon UNO5108 zone expander (a new "compatible" zone expander) and installed it as zone expander 1. It... still fails. It reports zones 9-16 as open at the same time as zone expander 2 (still a DSC PC5108) reports zones 17-21 as open. The only slight difference is that only zones 12 and 16 remain latched "open" after on the UNO5108. (But on either the UNO5108 or PC5108, each zone can still be cleared by shorting or disconnecting it briefly.) I am currently at a loss to explain this. I'm hoping someone with more experience can shed some light? I guess my next steps are to eye everything else in the system with suspicion. Like the RFK550 keypads with wireless receiver... could random wireless data be causing this?