DX-60A Bias issue?

[w2rik]

Guys! I removed the circuit breaker and installed a 2 amp fuse. The radio is loading up. It was either one of the .005uf caps on V3 or the Grid/Plate switch that fixed the problem.  I will post my voltages tomorrow because I still have the original issue with some voltages being off? Maybe it's not a problem, you can tell me.

I wish that I could shadow one of you when you work on a radio, you guys have so much knowledge and I learned so much from you in this thread, thanks so much!

Anyway, until tomorrow....

73!

[K4RT]

A 1950s ARRL or E&E handbook is also a good resource for understanding vacuum tube technology, especially the chapters covering transmitter & receiver construction.

[w2rik]

A 1950s ARRL or E&E handbook is also a good resource for understanding vacuum tube technology, especially the chapters covering transmitter & receiver construction.

The oldest ARRL Handbook I have is from 1977, but I do have the 2nd edition of the Abraham Marcus book, Radio Servicing from 1954.

[KB2WIG]

R,


Go here.                             http://www.tubebooks.org/technical_books_online.htm


Do it for the children.


klc

[w2rik]

R,


Go here.                             http://www.tubebooks.org/technical_books_online.htm

Whoa, awesome! Tnx OM!

[KA2DZT]

Guys! I removed the circuit breaker and installed a 2 amp fuse. The radio is loading up. It was either one of the .005uf caps on V3 or the Grid/Plate switch that fixed the problem.  I will post my voltages tomorrow because I still have the original issue with some voltages being off? Maybe it's not a problem, you can tell me.

I wish that I could shadow one of you when you work on a radio, you guys have so much knowledge and I learned so much from you in this thread, thanks so much!

Anyway, until tomorrow....

73!

Glad you're making progress.  None of those .005 caps on pins 1,4 and 6 would have cause the fuse to blow.   Do you still read a dead short on any of those three pins or has that short disappeared??  Do some transmitting,  see how things go.  If the fuse blows again, we have more work to do.

Most of us learned troubleshooting skills by doing just what you're doing.  The only difference is most of us did back in a day when there were no forums like this one to get some help.

Anyways, I think I can say that most of us enjoy helping out another ham with their project.

Keep the questions coming, someone here should have the correct answer.

Fred

[w4bfs]

back in the tv/cb shop daze, the tab mount chassis circuit breakers were commonly replaced items ....seems that after a while they trip on lower currents than rated for .... they went away but not until many were installed in new tvs

[KA2DZT]

back in the tv/cb shop daze, the tab mount chassis circuit breakers were commonly replaced items ....seems that after a while they trip on lower currents than rated for .... they went away but not until many were installed in new tvs

I still have a pile of those tab mount circuit breakers.

[W4DNR]

I'm watching this with great interest !!

Bob  W4RFM gave me a DX-60 and it's in the que for putting on the air.

Don W4DNR

[w2rik]

OK, here is my latest update:

My  Bias voltage is -80 in standby mode, here are the readings with a crystal in AM position. Reference is what is published on the schematic.

V1 6CL6 Crystal Oscillator
V2 6CL6 Driver
V3 6146 Final Amp
V4 6DE7 Modulator
V5 12AX7 Speech Amplifier

V2 and V4 is what I am concerned about? I don't have the VFO connected, but those readings would be way out. Is it normal to see such a variance between a rock and VFO? Need I worry or just get on the air and have funnnnn?!

XTAL V1 Pin 6 = 278v         REF V1 Pin 6 = 310v
XTAL V1 Pin 8 = 193v         REF V1 Pin 8 = 215v
XTAL V1 Pin 9 = -24v         REF V1 Pin 9 = -25v

XTAL V2 Pin 6 = 298v         REF V2 Pin 6 = 340v
XTAL V2 Pin 8 = 22v          REF V2 Pin 8 = 12v
XTAL V2 Pin 9 = -29v         REF V2 Pin 9 = -115v

XTAL V3 Pin 1 = 0.5v         REF V3 Pin 1 = 1.2v
XTAL V3 Pin 3 = 74v          REF V3 Pin 3 = 65v
XTAL V3 Pin 5 = -27v         REF V3 Pin 5 = -38v

XTAL V4 Pin 1 = 684v         REF V4 Pin 1 = 720v
XTAL V4 Pin 2 = 68v          REF V4 Pin 2 = 25v
XTAL V4 Pin 6 = 68v          REF V4 Pin 6 = 25v
XTAL V4 Pin 7 = -2.9v        REF V4 Pin 7 = -1.0v

XTAL V5 Pin 1 = 128v         REF V5 Pin 1 = 135v
XTAL V5 Pin 2 = 0.1mv        REF V5 Pin 2 = 0v
XTAL V5 Pin 3 = 1.3v         REF V5 Pin 3 = 1.3v
XTAL V5 Pin 6 = 83v          REF V5 Pin 6 = 80v
XTAL V5 Pin 7 = -0.7v        REF V5 Pin 7 = -0.7v

[W1RKW]

Good work Rik.  You're doing OK.  Learn by doing.

If the rig loads up and transmits ok you're probably OK at this point. As long as there's no smoke you're good to go.   

I would expect some voltage differences with a rig of this age and tubes of today.  most of those voltage numbers are within 10% and you'll have some variation to some extent due to the tubes themselves.

[DMOD]

OK, here is my latest update:

My  Bias voltage is -80 in standby mode, here are the readings with a crystal in AM position. Reference is what is published on the schematic.

V1 6CL6 Crystal Oscillator
V2 6CL6 Driver
V3 6146 Final Amp
V4 6DE7 Modulator
V5 12AX7 Speech Amplifier

V2 and V4 is what I am concerned about? I don't have the VFO connected, but those readings would be way out. Is it normal to see such a variance between a rock and VFO? Need I worry or just get on the air and have funnnnn?!

XTAL V1 Pin 6 = 278v         REF V1 Pin 6 = 310v
XTAL V1 Pin 8 = 193v         REF V1 Pin 8 = 215v
XTAL V1 Pin 9 = -24v         REF V1 Pin 9 = -25v

XTAL V2 Pin 6 = 298v         REF V2 Pin 6 = 340v
XTAL V2 Pin 8 = 22v          REF V2 Pin 8 = 12v
XTAL V2 Pin 9 = -29v         REF V2 Pin 9 = -115v

XTAL V3 Pin 1 = 0.5v         REF V3 Pin 1 = 1.2v
XTAL V3 Pin 3 = 74v          REF V3 Pin 3 = 65v
XTAL V3 Pin 5 = -27v         REF V3 Pin 5 = -38v

XTAL V4 Pin 1 = 684v         REF V4 Pin 1 = 720v
XTAL V4 Pin 2 = 68v          REF V4 Pin 2 = 25v
XTAL V4 Pin 6 = 68v          REF V4 Pin 6 = 25v
XTAL V4 Pin 7 = -2.9v        REF V4 Pin 7 = -1.0v

XTAL V5 Pin 1 = 128v         REF V5 Pin 1 = 135v
XTAL V5 Pin 2 = 0.1mv        REF V5 Pin 2 = 0v
XTAL V5 Pin 3 = 1.3v         REF V5 Pin 3 = 1.3v
XTAL V5 Pin 6 = 83v          REF V5 Pin 6 = 80v
XTAL V5 Pin 7 = -0.7v        REF V5 Pin 7 = -0.7v

Are these measurements Keydown on 80 meters?

Were these measurements taken at the bottom of the inductors' at the RF shunt caps?

What is your power out?

They look fairly close to what I have seen in DX-60's.

http://amfone.net/Amforum/index.php?topic=40809.0


Phil - AC0OB

[w2rik]

Tnx to all for your assistance! I have two questions.

1- Can I use this DX-60a to excite my AL-80 amp? Do I have to do anything or just hook it up and go?
2- Can I put the PS back to the way I had it? Right now I returned it to stock with only one cap. See attched images.

[Pete, WA2CWA]

Tnx to all for your assistance! I have two questions.

1- Can I use this DX-60a to excite my AL-80 amp? Do I have to do anything or just hook it up and go?

You should have some way (a scope) to monitor your modulated transmitted output and a way to key both the DX-60A and the amp at the same time.

2- Can I put the PS back to the way I had it? Right now I returned it to stock with only one cap. See attached images.

This is the way it is for the DX-60A. If it's working, leave it.

[DMOD]

Here is a block diagram for setting up your DX-60:


Phil - AC0OB

[w2rik]

Tnx to everyone, I think the rig will be FB now.

Phil, Tnx so much. I apologize because I just saw your last post now, I must have missed the email alert that I normally get when someone posts to this thread.

73 all,

Rik
w2rik