Mikey Helps The Technically Challenged - Me.

206.188.229.200

Posted on October 14, 2014 at 11:03:37

I sent Mike Samra a text (with a photo) around 10:30 this morning after changing out a 10 watt 1.2k resistor. I just asked which way I should go with my 500c because all that smelly smoke coming out of it didn't look right.

He texted me back and said to have a meter ready and that he would call in a half hour. Long story short, We (he) had every thing figured out in 5 minutes.

It must exhaust his patience to deal with some of us neophytes, but I guess that's what makes him so good at his day job as well - forming young skulls full of mush into automotive technicians.

Thanks Mikey......

Hide full thread outline!

when the magic smoke escapes...

mhardy6647

17:34:16 10/14/14

2

Camera?

geezerrocket

18:31:08 10/14/14

ahh, phone

mhardy6647

04:11:20 10/15/14

...

Show full thread outline!

when the magic smoke escapes...

mhardy6647

17:34:16 10/14/14

2

Camera?

geezerrocket

18:31:08 10/14/14

ahh, phone

mhardy6647

04:11:20 10/15/14

Ooooo - like a laser show it is!

airtime

16:04:54 10/14/14

It must exhaust his patience to deal with some of us neophytes

Michael Samra

15:30:46 10/14/14

RE: Mikey Helps The Technically Challenged - Me.

6bq5

12:23:27 10/14/14

6

RE: Mikey Helps The Technically Challenged - Me.

geezerrocket

13:32:09 10/14/14

5

RE: Mikey Helps The Technically Challenged - Me.

6bq5

15:23:01 10/14/14

4

RE: Mikey Helps The Technically Challenged - Me.

Eli Duttman

12:40:20 10/15/14

3

RE: Mikey Helps The Technically Challenged - Me.

Crazy Dave

15:25:15 10/15/14

2

RE: Mikey Helps The Technically Challenged - Me.

Eli Duttman

12:10:21 10/16/14

Thanks! (nt).

Crazy Dave

12:28:07 10/17/14

RE: Mikey Helps The Technically Challenged - Me., posted on October 14, 2014 at 12:23:27
6bq5 Audiophile Posts: 4392 Location: SF Bay Joined: August 16, 2001	OK, now that it is fixed - what went South? Inquiring minds want to know..... Happy Listening

RE: Mikey Helps The Technically Challenged - Me., posted on October 14, 2014 at 13:32:09

geezerrocket

6bq5;

It had a obviously fried resistor(s) of the wrong value when I received it.

Per Mikes' instruction I changed out the two wired in series fried resistors (to valve 9) to a single 1.2k 10 watt wire wound. I then turned it on and watched all the pretty smoke - Bwah Ha Ha!

Mike was kind enough to call me on his lunch hour and had me pull the output tubes, turn the volume down, then power it up and begin inserting 7591 tubes one at a time until the smoke appeared - Bad tube. A technically astute person would have noticed the cherry red tubes, but no one has ever accused me of being such. The bad tube was a JJ 7591S. I have had nothing but trouble with JJ power tubes, however, I have had good results with JJ small signal tubes. Anyway, I had no idea that could/should be done.

I am in the process of getting rid of the toggle on/off switch that was installed when the volume detent failed.

I will be getting a hold of Jim McShane for some grid resistors, Russian K40 pio .1uf coupling caps, matched quad of 7591's, and a couple of 12ax7 lps tubes. After that, it's off to the garage to power a pair of Heresy's.

Again; Thanks to Mikey and the other tech savvy members here that help the knuckle daggers like me on this forum.

This is precisely why I will be sending Mike my HK Citation II and AR SP3 (acquired very recently) later this winter. He sounds pretty excited about doing surgery on the SP3.

At this time he has my Sherwood S-5000 just about ready for shipping - Should be fun!

RE: Mikey Helps The Technically Challenged - Me., posted on October 14, 2014 at 15:23:01
6bq5 Audiophile Posts: 4392 Location: SF Bay Joined: August 16, 2001	Thanks- I asked in part as I once had a Scott 299 - that blew-up one night - I left it on.... a big wire wound resistor broke and took out something else - never went to fix as I was told that the Power Transformer was shot - I miss that unit - but I have better toys today.... Happy Listening

It must exhaust his patience to deal with some of us neophytes, posted on October 14, 2014 at 15:30:46
Michael Samra Dealer Posts: 36118 Location: saginaw michigan Joined: January 30, 2005	Not at all..If you can survive 1st and 3rd year automotive students,that prepares you for everything lol. "For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken

Ooooo - like a laser show it is!, posted on October 14, 2014 at 16:04:54
airtime Audiophile Posts: 11287 Location: Arizona Joined: February 4, 2003	Yum yum, Bar-B-Q tubes and resistor. If it wasn't for Mike I wouldn't have even bothered going back to tubes!!!!

when the magic smoke escapes..., posted on October 14, 2014 at 17:34:16
mhardy6647 Audiophile Posts: 16018 Location: New England Joined: October 12, 1999 Contributor Since: October 23, 2016	the best first thing to do ISN'T usually to grab the camera! ;-) all the best, mrh

Camera?, posted on October 14, 2014 at 18:31:08

geezerrocket

My wife has a camera - somewhere.
I have a phone with 13.5 mega pixels that is always with me.

I had it ready in case I wanted to snap a picture. I got a good one.

I thought it made for a interesting pic. When was the last time you saw a photo of a amp during thermal meltdown?

ahh, phone, posted on October 15, 2014 at 04:11:20
mhardy6647 Audiophile Posts: 16018 Location: New England Joined: October 12, 1999 Contributor Since: October 23, 2016	Call 911, then click the shutter; got it! ;-) Mrs. H broke down & got a smartphone this fall. My phone does have a camera in it, but it's got about two pixels (and their choices are black and white, or maybe just black)... all the best, mrh

RE: Mikey Helps The Technically Challenged - Me., posted on October 15, 2014 at 12:40:20

Eli Duttman
Audiophile

Posts: 10455
Location: Monroe Township, NJ
Joined: March 31, 2000

While it is work, recovery from a failed power transformer in Scott 299Cs, 299Ds, LK72As, and LK72Bs need not be hideously expensive. The "beefed up" replacement power trafo Triode Electronics sells for Dyna ST70s can be adapted to the need.

Use 1 of the 2X 6.3 VAC windings to energize the 6 power section tubes. Voltage double, with Schottky diodes, the other 6.3 VAC winding and 7812 regulate the resulting DC, providing for the 4X 12AX7 heaters. Half wave rectify the bias tap (a Schottky diode is preferred) and CRC filter the resulting "raw" DC to obtain the C- supply.

The scheme outlined above is made possible by the fact that the heater current draw of a 7591 is less than that of an EL34. :>D

Eli D.

Upgraded ST70 Power Transformer

RE: Mikey Helps The Technically Challenged - Me., posted on October 15, 2014 at 15:25:15
Crazy Dave Audiophile Posts: 14371 Location: East Coast Joined: October 4, 2001	As always, you are a fountain of information, Eli. Is there anything that works with a Scott 222D? Dave

RE: Mikey Helps The Technically Challenged - Me., posted on October 16, 2014 at 12:10:21
Eli Duttman Audiophile Posts: 10455 Location: Monroe Township, NJ Joined: March 31, 2000	Contact Heyboer. You may have to send the failed item in. Unfortunately, I am unaware of a suitable off the shelf power transformer. Eli D.

Thanks! (nt)., posted on October 17, 2014 at 12:28:07
Crazy Dave Audiophile Posts: 14371 Location: East Coast Joined: October 4, 2001

Vintage Asylum

Mikey Helps The Technically Challenged - Me.

206.188.229.200