I just got a SB-201 , and It was hacked badly , I take some pictures and post later .
I go to coffee shops for WiFi so some delay .
I did get the builders manual with the amp , I noticed some questionable solder points , a newer style cap soldered on the bottom side of the transformer board , then on the back of chassis , a aluminum box about 1'' x 1" x 3" riveted to chassis , one wire coming out of either side , the only mention of it in the manual was where to solder the 2 wires , but no mention of what it was ?
The 2 wires were cut and a short piece of small speaker wire looped around the box to connect the circuit the box made .
The stock fan was gone , the case had a hole cut , and fan mounted on top .
Also no tubes [ 572Bs ] , I will be looking for those , it sounds like the chinezz tubes are not the way to go .
This is my 1st tube piece of equipment .
I just got a Heathkit SB-201 amplifier.
It was hacked / modified badly.
I did get the Heathkit Assembly manual with the amplifier.
I noticed some questionable solder points.
John -
You purchased a PROJECT Amplifier.
Some of the metal cabinetry (as you described) may need repair/replacement.
Know a good auto body / metal fabrication shop? (this is not "Bondo work")
IF you are looking for a Plug-n-Play solution -- this is NOT such an amplifier.
1. IF you want an operational amplifier within the next few weeks -- do yourself (and everyone you may ask help from) and sell it as a Project Amplifier.
2. IF you have the resources (time and $$), then this can be a very educational process into mechanical and electrical assembly, soldering techniques, and basic electronics. Again IF you have no interest in acquiring these skills -- sell the amplifier.
3. Personally, I would completely disassemble and rebuilt the SB-201 replacing bad or damaged parts/components.
4. FIND a LOCAL ELMER -- experienced in these areas. Don't be a sucker for self-proclaimed 'experts'. Look for previous successful Heathkit, Elecraft builders or home-builders.
5. Harbach Electronics has many parts and assemblies to assist the SB-201 restorer/rebuilder. http://www.harbachelectronics.com/ma...00__sb201.html
Using Solid-State Transceivers With Older Tube Amplifiers
(some Hints and Kinks on the Heath SB-220/200 that can be useful in your application)
ARRL QST magazine - January 1988, page 45 http://www.tech-systems-labs.com/service/SB-200-MOD.pdf
K5DBX shows you what is possible in restorations (this is the larger SB-220 HF amplifier) http://www.k5dbx.com/
w9gb
Last edited by W9GB; 07-02-2010 at 03:40 PM.
We keep moving forward, opening new doors, and doing new things, because we're curious and curiosity keeps leading us down new paths. -- Walt Disney
w9gb ,
Thanks for all the links .
I knew this was a project when it was given to me in trade .
I am very familiar with many of the skills needed , I just light in the electrical component level diagnostics & repair .
I was very good with diagnostics in the auto repair bis , and household AC .
Doing lots of studying to get up to speed with RF and circuit level work .
I was looking at Heathkits in the 60s but sent to boarding school , with no Hams there , so did not think about until many years later .
I've always like diagnostics & repair of almost anything , most all that know me ask about what ever fails , and 95% of the time fix what ever it is , construction , auto repair , gunsmithing , electrical , plumbing , welding , machining just to name a few .
... a aluminum box about 1'' x 1" x 3" riveted to chassis , one wire coming out of either side , the only mention of it in the manual was where to solder the 2 wires , but no mention of what it was ?
What you will more than likely find, it is the 10~11 meter filter, rendering the amp unable to transmit on those bands. The SB-221 also had the same filter next to the input bandswitch, riveted to the panel.
Well, it does appear you have some passive components in the pics you have posted that have had the smoke allowed to be released from them, and more than likely would not be advisable to slap some tubes in and attempt to fire this unit up. Since I have no idea what shape the power supply tank circuit is in, I would again strongly advise that you not try to run it in it's present form, especially with damaged components.
Please remember and it cannot be overstated, that voltages produced in this amp can and will KILL YOU! No second chances.
Having said that, it truly is a project amp, and as W9GB has suggested, if it were me, it would be a complete tear down and component replacement.
Heathkit SB-201 , rebuild ?
Originally Posted by KD0CAC
