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Two relays NOT keying

LoneWolf TN

Active Member
Apr 2, 2005
357
5
26
OK, I just took my D&A Warrior to a friends. We did some checking, and two of the relays are not keying. Any suggestions? This is part of the reason why the amp is only doing half the watts it should be doing. Could this amp have been modified or are there some tests that can be done to tell why the two relays are not keying?
Nomad, Justin???

LoneWolf TN

PS, Looks like this box Good ol' BIGHAWAIIAN sold me has alot more issues than just the several bad tubes...
 

So, did you watch the relays using each of the lower-power modes, or just "High" side? Pretty sure it has TWO "high/low" power switches. At least one of the relays is used to cut in the low side, and won't move at all on one of the two high-side settings, or maybe two of them. Can't remember for sure.

The setting of those switches on the front will affect which ones close when you key, and which ones won't.

If you carefully discharge the power supply, check for continuity across each relay coil. Should be between 9000 and 10000 (9k-10k) ohms. An open coil would sure prevent a relay from closing. Not an uncommon failure.

Not an easy relay to track down and buy, if any of them have died.

73
 
d

Nomad, I checked the relays with power on low, (only high and low on this Warrior). The two relays that were not keying on high are kicking in on low setting.
Do I still need to check the continuity now that the relays are all working?
Also, I'm not sure if I have mentioned this before in past posts about this linear. There are 5 knobs on the face of the amp, two large and three small. All tuning knobs are working except two of the small ones - the small tune and small load knobs do nothing. The large tune and load knob and small driver tube knob are all working. All tuning sources on the rear of the amp are functional also.

LoneWolf TN
 
Hi Justin,
Belated congrats on the new job. Hope you don't have to deal with the suits too often. Corporate jobs sometimes come with unadvertised baggage, like guys in suits making outrageous promises to the customers. Good luck with all that.

Gotta wonder how long the '4001s lasted on a 110 Volt relay coil? Sounds like a borderline voltage rating to me. As if a 6AQ5 would care, after all? Tried using a TIP 50 and a PN2222 to replace the 6AQ5 a few years back. THEY definitely needed the diode, but it went across the TIP50, not the coil. Sure did increase the keying circuit's sensitivity below a half Watt. One tip on that, ditch the .01 disc from the 6AQ5 plate to ground before hooking the TIP50 collector there. The TIP50 will discharge the disc and surge-slam the TIP50 the first time you key it. CLue? Doesn't unkey until you replace the TIP50. Only had to learn that part of the picture once.

And LoneWolf, the small tune and load knobs work on LOW side ONLY. This setup was used only in the Warrior and the oldest smaller D&A linears. The ones that had three relays had a separate, small Tune and Load for LOW side ONLY. They did nothing on medium and high. Pretty sure your Warrior is the same on that count. It's a quirky setup that required three relays in the smaller Phantom and Maverick models. D&A abandoned the "3-relay" layout after only a couple of years for the smaller models, and thereafter used a different method for low side that only required two relays.

I'm pretty sure I posted a guide to identifying a "true" peak from a "false" peak on the Plate Tune controls in another post. Have you looked at the controls that DO work with this quirk in mind yet? Leads me to guess that at least one "Tune" control, (of the three that are active on Medium and High side) is going to the end of its travel, showing a "peak" with the plates either fully meshed, or fully apart. If so, this will put a crimp in the power you see. Just because you see a "peak" on each of the active Tune knobs doesn't mean it's a true peak. If each of the "no end-stop" controls shows TWO peaks, that one is functioning correctly. If it shows only ONE in a full turn of the knob, there's a coil out of whack that needs to be trimmed.

73
 
I have an old D+A thta has a two-relay system, running off of a relatively low DC voltage. Mine stopped keying, and I found that someone had installed an cap backwards in the keying circuit. The cap had actually fried quite a long time ago, but had enough capacitance left to keep working. Anyway, I replaced it, and the relays key fine now. Not sure if thats the problem with yours, but I thought I'd pass the experience along.
 

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