Repairing an Excal II...

[bklein]

I just obtained a bunch of parts that I will hopefully be able to resurrect into a working Excal II. Some of the issues/questions:
1) Koss yellow headphones cable is trash (but headphones work). Looks like the output is AC coupled by 1M resistor to ground and a series cap to the phones - embedded in the endcap. Is this standard?
2) I was thinking of putting a CTX headphone jack here so I could try different phones eventually. I'd like ideas for the headphone cable if you've had experience with this... Does someone sell the endcap or do I make my own - perhaps out of this one... Is the coil cable a must-have? I remember seeing the Peltor mod videos - but don't remember if they used a new cable.
3) Coil may not work as the bottom has cracks and water could have come in and trashed something. Haven't looked into this yet. Say its good, what should I fill the cracks with? I was then thinking of coating the bottom with truck bed coating(?)
4) The area around the battery connection on the pcb is corroded. The corrosion damaged some of the ground fill and a trace or two. What do you do to protect the exposed copper - coat with solder then what?
Epoxy, CA, some special conformal coating gook?
5) I'm going to look into waterproof jacks for headphones, coil, and battery but if you have suggestions please post.
6) Battery pod says for shallow water only. Was one for deep and another for shallow? This says Alkaline cells and has a bizarre connector. I want to go Lipoly when I get to it.

More questions to follow, I'm sure...

[bklein]

Spent hours googling yesterday.
1. Standard but some modders don't use it. Probably should to minimize DC offset power drain (?)
2. OBN seems most experienced with this. Will try calling him.
3. Still don't know.
4. Still don't know.
5. Using M12 type.
6. I need to think this one through. Unique standard connectors, not the best if starting from scratch and going custom lipoly.

I don't see anyone discussing whether hardwired phones have Koss lifetime warranty - calling them today.

[bklein]

No warranty on Koss yellow phones.

[localbug]

2. OBN sells the conversion kit, but he's busy right now. Check back again end of this year. Or try to contact Mal (google search Mal surffones)
3. Use Sugru
4. Use marine grease

[Carolina]

1- Yes standard but not needed. Yellow ground to cap can be cut and tie phones directly to two pin male connector via female connector. ( local hobby shop should have one if old connector can't be salvaged).
2- The old cap is cast but can be re-worked but needs practice. Your best bet is oldebeachnutjoe. He can make you a cap with the M12 connector installed for phones . 3M & Amphanol offer these
3- Marine grade epoxy, or two part epoxy should work. Truck bed liner is used frequently to replace coil covers
4- Not sure what your asking here. If trace and inserts are intact, I would leave them alone. My concern would be where did the water enter the tube? Caps, cracked tube or control knob o rings.
5- 3M and Amphanol both offer the M12 style connector and Souriau also makes a nice connector. Again you will need modified caps and Joe is your best bet. He closes shop for the spring,summer and fall months and re-opens in winter. December I think. There are others offering these caps but buyer beware. In my opinion he is the best by far.
6- There are two pods. The difference being the rateing of water depth. The Alkaline pod is 10' I be leave. The other 200' Unless your diving it will be fine. They both employ the Ikelite connector as does the charger and power cable.
LiPoly requires several mods as well as expensive charger. Better options available.
Hope this answers your questions. My concern would be is the board good? Before shelling out lots of time and bucks.

[Carolina]

You gave no mention of the tube and knobs. Are they intact? What revision is board?

[bklein]

You gave no mention of the tube and knobs. Are they intact? What revision is board?

Thanks for the helpfull info.
The board rev is 3.2. Has the blue electrolytics - I am thinking of testing these as I have a Sencore LC02 tester. Wonder if anyone else has thought about it.
I think the board will work as I have fixed the open traces I found. I will hook it up for a pretest before buying a straight shaft kit. The wire/cable I found at a local electronics store may or may not be ok for the coil cable. I need to scan a sample with the detector to be sure it isn't picked up. I want to test a few different candidates and see how they do.
I haven't looked at the tubes etc. for integrity issues - my intent for this detector is to be a backup to my CTX and for the control box to be out of water most of the time. I'm thinking of inline connect for the coil as a lot of risk trying to use the original end cap. I have the Amphenol M12 connectors - they have a real questionable connect, kind of gritty as they tighten. Seem like Chinese knock offs but got them from Mouser.... I'm thinking if I embed one in the endcap it will get more stress than if it were inline instead. I might use Tony Eisenhower's idea of 8 conductor cable out the cap to support the pinpoint mod as well.

[Carolina]

3.2 is the latest Excal. II

[bklein]

Cool! Probably shouldn't be concerned about the caps then.