# ALAMO PARAGON 2575 challenge



## cdayo (Jan 28, 2014)

Pulled this apart today as a few weeks ago it was giving me some static and popping noises. I did a bit of research and I see a few things that I think need to be tended to, but I want to confirm it before I take any next steps. 
I attached some pics to look at...what we have here is an Alamo Paragon Bass from August 1974. Sounds great with bass and guitar
*THERE IS NO SCHEMATIC FOR THIS PIECE*

I have never tried to service the amp myself (today I resoldered some lousy joints and cleaned the pots) but I took the amp in a year ago with 'no sound' to a Toronto tech who did some work on the OT. Apparently it was no good, however as I am examining it today, it still looks original. Any input would be great!

Here is a picture of the board and the transformers


Ya I love the look of that swirly goo too.


The things I want to address are...
1) How do I check that the Mallory cap mounted on the chassis? Is there a way to remove the shield without unsoldering the cap?
Top


Bottom


2) Some of the multi coloured caps on the 'board' are cracked. What is the affect on the amp?


3) It looks like there is a small leak at the base of this lead of the filter cap. I'm guessing that needs replacing. The other is fine... But what about the small black caps on the board? They look to have leaked as well (see above pic on right). Should I replace those too?





4) You can see that the death cap is present. I am thinking it should be replaced before next use and along side the installation of a 3-prong power chord.


5) What is with the blue wire with the electrical tape? It is coming out of a transformer but goes nowhere apparently.


6) Is that a burned resistor I should replace? (note another cracked cap and leaky black cap?)


Also I have noticed many of the lead wires to the tubes are not twisted, as I have seen in many other amp builds. Is this something that reduces hum? Would it be good to implement a similar practice in this amp?


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## keto (May 23, 2006)

ALL electrolytics, including the cap cans, should be replaced. The cap cans have to be soldered out BUT can be left in and bypassed, using modern electrolytics of the same value(s).

If the OT is shot, you're never going to get any output out of the amp until it's replaced.

The cracked tropical fish caps may or may not be working, you'd have to take them out of the circuit and test with a meter that can measure capacitance. Similarly, resistors you have to take one end off and measure with a meter to see if they're still relatively close to spec value.

Yes, bypass the death cap and put a properly grounded 3 prong cord in it.

The blue wire capped off with tape is probably for a rectifier tube. Not needed, ignore.

I'm no pro but this much I know.


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## cdayo (Jan 28, 2014)

Thanks for the tips. I should note the amp works well and sounds good so there is no doubt the OT works...I imagine the fish caps are working too because the amp works, that being said they will probably fail at some points too if they are cracked, no? IS there any way to tell the value of these caps? there is no listing on them


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## greco (Jul 15, 2007)

cdayo said:


> IS there any way to tell the value of these caps? there is no listing on them


I think this is what you need: http://www.csgnetwork.com/capcccalc.html

Cheers

Dave


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## cdayo (Jan 28, 2014)

Thanks dave!

PS. Thoughts on that resistor? it looks burned, its kind of hard to find exact information on these sorts of things.


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## greco (Jul 15, 2007)

cdayo said:


> Thanks dave!
> 
> PS. Thoughts on that resistor? it looks burned, its kind of hard to find exact information on these sorts of things.


I would unsolder it (at one end...as Keto explains for resistors)... and measure it on your meter. 
Then compare your measurement to what it is spec'd for ...looks like 22 Kohms at +/- 5% *(you need to confirm that)* ...I'm guessing that it is rated for 1/2 watt of power. 

If it reads close to what it should...you can solder it back in place.....and then worry that you should have replaced it..

*OR*

Replace it ....and sleep well. 

PLEASE... Wait to see what others advise you to do. Many have much more knowledge and experience than I have.

Remember to be safe around those big caps!

Cheers

Dave


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