Ripmax Pathfinder repaired & working well !

[Phil_G]

Ebay watchers will probably have seen the really nice Ripmax Pathfinder set which surfaced recently.
The buyer, David, has asked for a Single-Channel Actuator Emulator, which I assembled yesterday
and I was pondering methods of connecting it to Davids Pathfinder receiver. Relay? Optocoupler?
I had an idea that somewhere in my stash there might be a Pathfinder transmitter, and did some digging.
Sure enough, I found it, and - bonus - inside the case was a Pathfinder receiver I didnt know I had !
Of course the receiver didnt work, but after swapping a couple of duff electrolytics, it works perfectly at over 50 years old !
The transmitter worked right away, they always do, a good quiet carrier on the Yaesu comms receiver and a clean & solid tone.
I found the Pathfinder receiver has an open-collector output so is able to drive the emulator directly - previously we've had to use either a relay
or an optocoupler, but in this case everything works perfectly wired directly to the Pathfinder receiver with no need for either!





Here's the old video from 14 years ago (though nothing has changed):

[Phil_G]

I posted Davids S/C Actuator Emulator today but I was so chuffed to discover I had a (now) working Pathfinder outfit, I assembled another one for it, so its now a fully functional demo set
Would I fly it? Possibly, after a range-check, though the button is just awful, long spongy travel and no click... and it is a super-regen. I have always intended to make a "Wee Willy" which was the S/C slope trainer flown by SSA members, designed by Phil Scaife. Theres no plan but its a simple boxy model and I do have a couple of photos to work from. That would be pure nostalgic fun!

[HenkB]

Ever tried that before? I mean flying single channel on 27 mc using a superreg receiver recently? May be not that safe but compliments if it's even possible.

[Phil_G]

27 is fairly quiet where we fly Henk, any occasional CB activity tends to be in the evening on the legal FM high-band - but another consideration is we're approaching the peak of sunspot cycle 25... given a clear band it would be great fun. We do tend to fly close-in at Baildon. We'll see
Maybe add a D/T so it cant make its escape!
First job is to range-test the Pathfinder... it might not be up to the job...

[Stew]

I have a pathfinder transmitter and receiver in my workshop (I think you gave me the receiver I have Phil).
They both work but I've not range tested it.
You're right, the button is awful!
I have the box too, which Shaun assures me is a tampon box!

Stew.

[Phil_G]

Davids ebay Pathfinder set didnt work so he sent it to me. Testing showed the tx is ok, but the rx was locked on.
I changed a couple of electrolytics and its working now but the range is only about 30 feet. It tunes nicely but thats it.
I checked my own Pathfinder and - guess what - range is also about 30 feet !
The regen hiss is there but very quiet and I suspect its not oscillating/squegging properly.
I'm going to change out all the transistors, apart from the BFY51 output they're all common-or-garden BC108s or 'TUNs' as Elektor would say.
I'd change the C280s but my stock is probably as old as the Pathfinder
A schematic would be nice but I cant find one anywhere, might have to trace it out. Its not (as many were) Terrytone-based as it has no Ardente transformers. The BFY51 output is open-collector so it can drive the actuator emulator directly with no interface. Which is nice

Anyone have a schematic by any chance?

[Stew]

Phil I'm sure there was one on the old Norcim site? I may very well be wrong though. Just a vague memory. May be worth a look though?

Stew.

[Shaun]

Hi Stew,

The boxes weren't tampon boxes. The Pathfinder set manufacturer was located next to a company that made sanitary towels.apparently they got all the ones that failed the quality checks f.o.c. and used them for packing inside the tx boxes.

Shaun.

[Stew]

Hi Shaun.
Ah yes, that's right. My mistake. I will absorb the facts better next time!

[Shaun]

Absorb.