Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: Prev 1 2 3 4 [5] 6 7 Next   Go Down
  Print  
Author Topic: Titan 425 Help (Blowing Fuses)  (Read 13834 times)
KO4NX
Member

Posts: 179




Ignore
« Reply #60 on: February 07, 2013, 07:57:32 AM »

Well Rocco's amp and PS arrived on Tuesday   I unpacked it tonight ( he did a great job of packing it) and I began troubleshooting it.  So far I found 3 shorted diodes in the rectifier string.  I think that could do a number on a 1.5amp fuse.  Rocco said that the last owner said he replaced the filter caps but I am suspect of that.  The capcitance was written on the bottom of the caps.  Does anyone know if Ten Tec did this?  Lou

I do not think Ten Tec did this, as both of my PSU's do not have the Capacitance value written on the bottom of the capacitors.   
Logged
W1QJ
Member

Posts: 1443




Ignore
« Reply #61 on: February 07, 2013, 08:53:32 AM »

These caps are Mallory 400uf 450v with 525v surge.  They are the big long ones.  I think the new ones are short now.  Anyhow they might be good.  If someone bought them from Mouser lets say, Mouser I doubt would have marked them, the buyer would mark them?  Why...If he buys 8 of them he can't match them.  Just thinking out loud.  K1FO of our Lunar Link business did mark his caps and matched them as close as possible when installing them.
Logged
KE3WD
Member

Posts: 5694




Ignore
« Reply #62 on: February 07, 2013, 12:14:42 PM »

Probably someone trying to troubleshoot at some time thought that marking the caps would make it easier.  I've seen all sorts of things like that over the years.  Like the one that had almost everything labeled underneath the chassis with laundry marking pen and even paper tape tabs around zitter and cap leads.  Pulled the bottom cover on the bench and the darn thing looked like the old fashioned hair up in curlers.  This is why it is good to have technicians at other benches in the same shop.  You've gotta have someone else around to call over and say, "get a load o' THIS!"    <grin>

So many are so wrapped up in the 'replace the caps' syndrome these days.  Perfectly good old Spragues lying in the trashcan with their leads clipped.  We get plenty of older and newer things in for repair these days where all the electrolytics were blanket replaced in an effort to fix symptoms that have nothing at all to do with filter caps.  And the reason we get them is that they still don't work.  A surprising number also have caps replaced backwards, or just plain wrong, too.  Following the easiest path, I suppose. 


73
Logged
K2XT
Member

Posts: 39




Ignore
« Reply #63 on: February 07, 2013, 12:19:37 PM »

If Lou was a cardiologist, and I had a heart attack, I would tell the ambulance driver to take me to Danbury Connecticut to be treated by the worlds best cardiologist.

"When your life depends on it, you want the best."
Logged
KC4MOP
Member

Posts: 729




Ignore
« Reply #64 on: February 07, 2013, 02:09:34 PM »

The Titan I had at one time had the original caps in the HV and it was thought that it was a good maintenance thing to shot gun them all. It wasn't that hard or outrageous in cost from Mouser.
I never heard of matching capacitors for an HV power supply.
There is a purpose for the equalizing resistors across the caps and diodes in that circuit.

http://audiosystemsgroup.com/Titan.pdf

Fred
Logged
W1QJ
Member

Posts: 1443




Ignore
« Reply #65 on: February 10, 2013, 01:20:40 PM »

Well folks the final word on Rocco's power supply problem is that it has a short between the primary and secondary.  It is a weird sort of thing, it appears the short goes through ground.  It's funny, if you leave off the ground from the wall socket all is ok.  Connect it and bang.  I isolated the transformer primary and secondary from the circuits and there is continuity between the primary and secondary windings.  I checked it against my 425 transformer and the same continuity is not there with mine.  SO we are looking at possiblities for a transformer replacement.  I told Rocco we can probably use an Ameritron Al-800H transformer.  It has the proper HV secondary and also has the filament winding.  I'll need a 20vac transformer to make the needed 28vdc.  Plenty of room in there to do the retrofit.  Yup, I know, a bad transformer is the worst of the problems.  So we will see what Rocco decides to do.
Logged
KO4NX
Member

Posts: 179




Ignore
« Reply #66 on: February 10, 2013, 03:03:33 PM »

Yikes, that is not good news at all Angry

Has anyone looked into one of the Dahl replacements?  I was under the impression someone has taken over Dahl's designs, which at one time included a replacement 425 Transformer.

Rich
Logged
W8JX
Member

Posts: 5478




Ignore
« Reply #67 on: February 10, 2013, 03:13:34 PM »

Yikes, that is not good news at all Angry

Has anyone looked into one of the Dahl replacements?  I was under the impression someone has taken over Dahl's designs, which at one time included a replacement 425 Transformer.

Rich

Harbach did but they as discontinuing them around 15th of this month. Said too costly to make a profit  in todays market. Looking for a buyer.
Logged

--------------------------------------
Entered using a  WiFi Win 8.1 RT tablet or a Android tablet using 4G/LTE or WiFi.
KA5N
Member

Posts: 4380




Ignore
« Reply #68 on: February 10, 2013, 03:22:04 PM »

I wonder if there is insulation rubbed off the wires of the two windings?   Might be difficult
to locate, but would be worth a try and cheaper than a new transformer.  Of course there
might be an internal short inside the transformer, or something sharp stabbing through the
insulation. 

Allen KA5N
Logged
WU2M
Member

Posts: 29




Ignore
« Reply #69 on: February 10, 2013, 03:24:43 PM »

I E-Mailed Harbach a couple of weeks ago and here is the response:

Hi Rocco,

The cost for a new Ten-Tec 425 transformer is $650.  We can rewind the old unit (assuming the cores are still good) for $350.

Factory lead time is approximately 4 weeks.

 Regards,

Jeff

I'm not sure what I am going to do yet. I will make some phone calls tomorrow and then make a decision.

Rocco

Logged
KE3WD
Member

Posts: 5694




Ignore
« Reply #70 on: February 10, 2013, 04:32:42 PM »

...I told Rocco we can probably use an Ameritron Al-800H transformer.  It has the proper HV secondary and also has the filament winding.  I'll need a 20vac transformer to make the needed 28vdc.  Plenty of room in there to do the retrofit.  Yup, I know, a bad transformer is the worst of the problems.  So we will see what Rocco decides to do.


Hey Rocco,

What do you find to bad about this plan? 

If Rocco can convert to the rather readily available and likely lower cost 800H xfrmr, I'd say that would be an upgrade from the existing situation. 


73

Logged
W1QJ
Member

Posts: 1443




Ignore
« Reply #71 on: February 10, 2013, 04:35:07 PM »

I wonder if there is insulation rubbed off the wires of the two windings?   Might be difficult
to locate, but would be worth a try and cheaper than a new transformer.  Of course there
might be an internal short inside the transformer, or something sharp stabbing through the
insulation. 

Allen KA5N

I inspected the wires best I can see.  It seemd like the short is inside the transformer.  I suppose it can be rewound.
Logged
WU2M
Member

Posts: 29




Ignore
« Reply #72 on: February 10, 2013, 05:04:13 PM »

...I told Rocco we can probably use an Ameritron Al-800H transformer.  It has the proper HV secondary and also has the filament winding. I'll need a 20vac transformer to make the needed 28vdc.  Plenty of room in there to do the retrofit.  Yup, I know, a bad transformer is the worst of the problems.  So we will see what Rocco decides to do.


Hey Rocco,

What do you find to bad about this plan? 

If Rocco can convert to the rather readily available and likely lower cost 800H xfrmr, I'd say that would be an upgrade from the existing situation. 


73



I like to run digital modes. RTTY & SSTV and was concerned that maybe the Ameritron transformer would not be able to handle it.
Logged
W8JX
Member

Posts: 5478




Ignore
« Reply #73 on: February 10, 2013, 06:56:30 PM »

I wonder if there is insulation rubbed off the wires of the two windings?   Might be difficult
to locate, but would be worth a try and cheaper than a new transformer.  Of course there
might be an internal short inside the transformer, or something sharp stabbing through the
insulation. 

Allen KA5N

I inspected the wires best I can see.  It seemd like the short is inside the transformer.  I suppose it can be rewound.

A rewind would be about as good as new as possibly better depending on materials used.
Logged

--------------------------------------
Entered using a  WiFi Win 8.1 RT tablet or a Android tablet using 4G/LTE or WiFi.
KE3WD
Member

Posts: 5694




Ignore
« Reply #74 on: February 10, 2013, 07:38:09 PM »

It has been my experience that a good rewinder often yields a better job than original. 


73
Logged
Pages: Prev 1 2 3 4 [5] 6 7 Next   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!