R.I.P. my Cornet

Doc Jr 8156 · « **on:** 22 Oct 2004, 03:13 am »

Without any warning the transformer of my Cornet smoked after 30 seconds upon turn-on. It was alive and well last night so I'm dumbfounded why this happened. What really puzzled me was that the fuse was intact and the capacitor supplied by Jim for the turn-off thump was not even hot nor any other part caps on the board warm to the touch. The Cornet was supplied by my Transcendent Balance Power tranny ever since the I assembled. All tubes are new. My primary question would really be, did damage occured to any parts on the board resulting from this? How would I check for parts integrity once again? By the way my tranny is a Hammond 270BX. Suggestions on how to proceed greatly appreciated. Godspeed.

hagtech · « **Reply #1 on:** 22 Oct 2004, 04:58 am »

Most likely no harm was done to anything. Just another of those unfortunate 270BX stories. We've lost a few of them in this circle. I spoke about this with Jack Eliano at RMAF and he mentioned the 200 series was not constructed too well. Nothing to do with circuit, just that their internal insulation is weak and they tend to short turns in the primary.

Best thing is to replace it with a 370BX. That series is much better designed in a number of ways. Wish I had known this earlier. All my newer products use the 300 series. So far the reliability has been great.

jh

Doc Jr 8156 · « **Reply #2 on:** 22 Oct 2004, 03:49 pm »

Thanks Jim. I will. One question though, will the wiring installation be the same? Sorry, not that electrically-inclined. Godspeed.

GRD · « **Reply #3 on:** 22 Oct 2004, 09:53 pm »

the demise of your 270BX. Thanks for posting. Now I know that it's not an infant mortality problem. So, I won't be suprised if my 270BX gives up someday. And, I'll make sure it's not sitting on something expensive.

(What will peeve me the most is the time I spent removing the bells, cleaning, and repainting them.)

hagtech · « **Reply #4 on:** 23 Oct 2004, 02:43 am »

Wiring is the same, except you'll have extra grn/yel and violet wires. Just tie them off unconnected.

More info here:

http://www.audiocircle.com/index.php?topic=4328

jh

Doc Jr 8156 · « **Reply #5 on:** 23 Oct 2004, 04:40 pm »

Thanks Jim. I'll check the link when I get my 370BX. GRD, exactly the same sentiment I had. It took some effort to remove, sand, primed then paint those bells to our liking and I have to do it all over again. Godspeed.

Doc Jr 8156 · « **Reply #6 on:** 28 Oct 2004, 04:42 am »

Jim,
I got my tranny (370 BX) today and since my Cornet PCB is the old one I just want to make sure about the lead connections. The primaries will be which 2 leads, the BLK and WHT? I know that the GRN/YEL/RED wires are interchangeable but not sure which leads connect to the switch. I read the thread you posted above but that corresponds to the new Cornet PCB power connections. Hope my Cornet will sing again soon. Thanks. Godspeed.

John Revilla

hagtech · « **Reply #7 on:** 28 Oct 2004, 06:43 am »

Oh yeah, you have to strap the dual primaries together. Brown and White together for Neutral, Blue and Black together for LINE. The other 4 (with stripes) are no connects.

jh

Doc Jr 8156 · « **Reply #8 on:** 5 Nov 2004, 10:17 pm »

Jim,

Cornet is singing again with the 370 tranny. One question, is it just me or the old cornet config fitted with the 370 have more bass output than the one with the 270BX? I only changed resistors in 2 places? Thanks.