[dexter1]

In a private message i was helping out a forum member with RM4T/RM5T bus termination on the Reality Engine on Crimson/4D system.

I opened up my Crimson to measure the resistor network pack and to my surprise the values measured do not seem to make much sense. The outermost two pins have 0.5 Ohm resistance and the rest have infinite resistance i.e. they are all open circuit.

So maybe there are diodes inside the pack but my diode checker didn't find anything.

This is a picture of the component:



Can anyone shed som light on this part?

[weblacky]

I’m tying to search here, and like you, having trouble. But when I typed in 8181 array, the search suggested that ceramic capacitor arrays existed.

That combined with your infinite resistance...could you try a cap measurement tool on this?

While I cannot locate this exact form factor (only SMD form factors). This does look like it could be several ceramic caps in a single package and instead of a termination resistor array it could be a grounding decoupling capacitor array?


Let us know what a cap measurement meter says on this. That would explain the “all over” ohm measurements.

[dexter1]

I pulled it out again and measured capacitance assuming it is either a capacitor array or capacitor network.

Nothing, reversing the leads, going across all the pins, again nothing. If there are capacitors inside this package they are less than 1 nF

Tried diode measurements both ways, again nothing.

What i am certain of is that the (marked) first pin and last pin are wired together, and that any network component ending in a pin in positions 2-9 has a common ground with pin 1 and 10.

[Irinikus]

The capacitance here could be in the picofarad range.

[weblacky]

Wow, good find!

Dexter1, what about trying the cap measurement again based on what Irinikus found? You're right in that an normal multimeter cannot recognize a pF cap, it's too fast in charging to be measured that way. You could place like 0.1v on one of them from a limit current bench PSU, then check if current flows after charging. That might be an easy way to prove it's some kind of cap. Caps stop the flow of DC once charged. If you placed in in a very limited BENCH PSU circuit (0.1v at like 10mA), the PSU will say it's providing 0.000 amps once they are charged, right?

I mean I have other equipment that could easily show pF...but a standard piece of equipment people have to prove this...I'm drawing blank, other than the current flow idea...

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Either Way, I still haven't found anything about those markings...frustrating to say the least.

[SuigintouLain]

Edit 2: Update, I ended up making a capacitor array matching the below configuration and it gets past the initial error, but is still acting weird. My DG may also be at fault.

Edit: 8*I*810N22. Look at the 1 and the I for the serifs.

Making a ton of assumptions:

RC (assuming this is made by the company who was the only result for the correct part number) = Series
8 I = unknown
8 = elements
10 = pin count
n22 = .22nf -> 220pf (common capacitor network value)
ø20 = 20% tolerance?

A modern equivalent might be Vishay 20110D4X222M5P (or N5P for 10%)