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Discussion in 'Amplifiers' started by HITEK-REDNEK, Dec 1, 2010.
Amp holding key too long
They only thing that will hold in the relay after you un-key the mic is an eletrolytic capacitor. They are the small can type objects. They function just like a battery that charges up when you key the mic, then when you un-key the mic, the charge they received reverses and is enough to hold the magnetic relay in for a few seconds. The more uf or micro-farads the capacitor is, the longer the hold time. It sounds as if someone may have installed a capacitor with too many micro-farads. You said the amp is automatic sideband so I assume it does not have a SSB switch. If you do find the capacitor that is holding the relay in, you can break one side of its connection with the board and run it through a switch. Any kind of small SPST switch will do as the voltage and current will be low.
Their are MANY revisions of the 225 series of amplifiers, but only a couple electrolytics in each one.
Usually, you find 2 to 3. 1 or 2 of them will be across the 12 volt input wires. They are their to keep LOW freq oscillations out of the power wires, and to keep high freq bleed to a more limited extent, from making it to the power wires. LEAVE THESE ALONE!!!! You will know you have found them because it will go from the red leads (positive) to the ground leads. Period.
THEN, near one of the relays (usually the one by the input side), you will find ANOTHER blue capacitor, standing up 9 out of ten times. THAT'S your SSB delay cap.
Don't use SSB, clip it out. Use it infrequently, clip one side, install a switch in series, and that becomes your SSB / AM switch.
RECENTLY, on the 225 and 300 boards, I've noticed a spot on the front for a SSB delay switch. Check near the wiring for the other two switches, you might find a couple solder pads marked SSB or DELAY. Their will be a jumper across them. Delete this jumper. That kills SSB delay. Install a switch, that gives you AM/SSB.
Hard to give real step by steps without pictures, considering their has been probably 15 revisions of that amplifier since it appeared in the early 90s... As well as having boards mfg'ed in 5 or 6 different countries. BUT, these generics should get you where you need to be... If not, then get your hands out of the amp.
You are on the right track
Yes, what you said about coming off one pin of the capacitor with a wire to the switch and then going back to the board where the cap was lifted with a wire from the other switch post is exactly right. You can lift either pin of the capacitor, however, personally I like to use the negative side when running to a switch like that due to the fact that running wires without voltage on them is safer from the shorting out standpoint than running a wire with voltage that may break and cause something to burn up. Only if the wire coming from the negative part of the board falls onto a part that contains voltage will something bad happen. Also should the switch short out, the only thing that will happen is the relay will hold in like the switch was on alerting you that something is not right. You are on the right track so just warm up the ole iron and go at it.
Like I said clipping one leg made AM delay better but SSB was then a problem. I know there was a group of us that bought these in the mid 1990 and we all complained about this and some got rid of the amplifier because the delay drove them insane when people wouldnt wait before keying up and you would miss the beginning of what they said because of the delay.
Some of the guys clipped on leg of the Cap. It actually p!$$ed me off at first aswell that they did this but soon after there was a new batch available and they didnt do this. I would imagine that is an older one you have aswell unless they actually did this again. I dont mind it because it is supposed to keep people from being Roy Rogers (quick) on the trigger or key hence the name (SSB DELAY).
The problem is you can tell people over and over to take a breath or take a few seconds before keying and they dont grasp it and key as soon as you unkey making your conversation or contact just shy of being one sided.
pics of my galaxy 225
I think I might have them on here now