Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: ginger on November 07, 2018, 10:03:36 am
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They don't take solder easily , and are riveted to the chassis , or I would replace them.... any tricks to remove whatever is stopping the solder flow ?
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More heat. Use flux. Small wire brush helps sometimes.
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Give us some details about your setup...what soldering iron or soldering station are you using? What is your technique?
Looks like you are working on a Silvertone 1484 or 1485? The terminal strips that Silvertone used weren't any different than the other companies were using and are good quality so they should be fine to work with. One thing Silvertone did do was to wrap the leads around and through the terminal strip holes, so you need to use a solder sucker to get all the old solder out before you try to pull the leads from the old part out. That is a little more difficult than some amps where they just stick the lead in the hole, but it is good quality construction to do it that way.
You will find that your soldering technique will improve 300% if you use a temperature controlled soldering station rather than a xx watt soldering iron. A wide tip helps to transfer heat to the joint, as does pre-tinning your tip. Making sure the tip is clean is extremely important too. Flux can help though I rarely need to use it myself. Leaded solder is much easier to work with than non-lead solder also.
Greg
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One more thing, when that amp was new the repair technicians would likely be using a Weller 140 watt gun rather than a 40 watt pencil. The 260 watt big brother was used for heavy stuff like direct soldering to steel (or copper clad) chassis or replacing a twist lock cap can. Pencils were used mainly on PCBs or other delicate stuff. Most all shops would have at least one of each of these...
https://www.amazon.com/Weller-8200PKS-120-volt-Universal-Soldering/dp/B002YDMZF4/ref=sr_1_6?ie=UTF8&qid=1541612204&sr=8-6&keywords=weller+soldering+gun
https://www.amazon.com/Weller-D550PK-260-Watt-Professional-Soldering/dp/B00002N7S1/ref=sr_1_3?ie=UTF8&qid=1541612204&sr=8-3&keywords=weller+soldering+gun
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I agree on all the points here. Basically I have some I use that are pretty crusty, I get a wire brush and scrub the crap outta them to get off the oxidation, and then use flux to ensure extra bonding of the solder.
~Phil
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Another trick is to apply new molten solder. For some reason, the new molten solder helps melt the old stubborn solder.
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I've been using a Weller WP35 for years with no problems , and works fine with NEW terminal strips.... but not these old ones on this Silvertone 1485 .
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35 watts is not enough heat for those oxidized terminals. A bigger iron/gun and flux will remove the oxidation and allow the terminals to take solder properly. Once the terminals are tinned properly your small iron should work OK.
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This is my second 1485 in 3 weeks... guess I'll have to use my big $ 17.00 Sears Craftsman soldering iron .
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back
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I expected these amps to sound kind of chintz
y... NO... full and really nice
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Yeah these are a great sounding amp in stock form. They also are greatly compromised by layout issues and the small output transformer so that if you planned to mod one for more gain it can get noisy with a high hum level, and the frequency response will be somewhat narrowed due to that really small output transformer. That stock transformer has a 4 ohm tap for use in the 1484 and a 2.6 ohm tap for use in the 1485, so if you eventually decided to upgrade to a larger transformer you would need to keep those ratios in mind if you wanted to have the stock arrangement. If you're using a different speaker setup then it wouldn't matter so much. I bring that up because Weber has a replacement transformer for these and it is the standard 4, 8, and 16 ohm impedance. They're a pain to work on too, but sometimes its worth it. The reverb on these does sound chintzy though. :)
A bigger iron will help for sure for those old oxidized terminals, but you can do both tasks with a temp controlled station. Might think about an upgrade in the future. My soldering technique improved a lot with the temp controlled station, and I rarely go through iron tips nowadays too whereas they used to wear out much more often with the non-temp controlled station irons even with proper care.
Greg