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What amp is this? [message #8907] Sat, 22 September 2007 23:17   RickV Messages: 6 Registered: September 2007 Location: DFW area Junior Member I picked up a Kustom 200 guitar head at a garage sale today (for $20). They said it didn't work. It's black T&R with two channels. Both have norm/bright switch. The channel on the left has trem & reverb. The reverb channel seems to work good after I cleaned up the pots with some contact cleaner. The other channel gets a very faint sound. I'm thinking the volume pot is shot. I can't find any markings on it anywhere (inside or out) specifying what model it is, serial number or anything. I'm assuming it's a "B" series. It's got the plexi front and two prong cord. I'm thinking it's late `60's or very early `70's. I want to order a schematic, but don't know what model I should order it for (K200-B1, B2...B6). What ohm output are these heads? 8 ohm? Any idea where to find replacement power filter capacitors (4500 MFD @ 50 VDC)? It has two of these mothers. They may be good, but at nearly 40 years old, I figure the best this to do is change them out. The garage sale also had two 2x15 cabs (Red & black). The guy wanted $150 for all three, but the cabs were in somewhat rough shape. I opened up the back on one & it had one CTS 15" & one Jensen C15L. Both were loaded the same. Too bad they didn't have JBL's. They'd be sitting in my garage, now. Rick V Report message to a moderator

Re: What amp is this? [message #8911 is a reply to message #8907] Mon, 24 September 2007 15:54 chicagobill Messages: 2005 Registered: April 2003 Senior Member Congrats on your purchase, and welcome to the board. There are three types of plexi front amps, Frankensteins, 200A's and 200B's. Because you have bright switches, that rules out the Frankensteins, so you either have a 200A or a 200B head. Early A's have circuit breakers (white pushbuttons) mounted on the front panel on either side of the power switch. Later A's have an internal fuse like the B series amps. The A's have the power output transistors mounted on the bottom panel of the chassis. Because of this, they have four brass mounting studs that elevate the chassis away from the case bottom. These are easily visible when looking at the rear of the amp. The B series amps have the output transisitors mounted on a small aluminium extrusion that places them inside the chassis, so the bottom sits flush to the case bottom. Electronically, the A's have a pre-amp that is driven fron a single 24 volt power supply, while the B series pre-amp uses a plus and minus 8 volt supply. Both versions were designed to work best into a 4 ohm load. Most A's have the foot switch jack mounted on the rear panel (usually a DIN connector), while the B's have 1/4" stereo jacks mounted on the front panel. Unless someone has removed the back panel id plate, my first guess would be that you have an A-series head. Nearly every B-series head that I've ever seen always has an model/id plate. As for your dead channel, I'd suggest first checking for any loose parts or bad solder connections on the board. Then check all of the transisitors and then all of the electrolytic caps. My guess would be a bad cap if it has lost most of the signal. Hope this helps, Bill Report message to a moderator

Thanks Bill! [message #8915 is a reply to message #8907] Mon, 24 September 2007 19:16   RickV Messages: 6 Registered: September 2007 Location: DFW area Junior Member It's a "B". I got the verb channel working good. After extensive cleaning of the pots & boards, I plugged it into my Vibrolux Reverb speakers (two 75 watt Eminence Ragin Cajun's). It's very loud and no hum, hiss or crackling going on. The non-verb channel is dead with just a faint signal when I mess with the volume knob. I'll change the volume pot & see what that does. I also ordered a couple filter caps last night (6500 MFD @ 75 VDC). I'll see if they make any difference. I've got some literature on the way. I'll check all the resistor values & change the coupling caps. I can't get over how good this thing sounds. Did I say it's LOUD! This thing cranks! One more question. What's the RCA jack on the back for? Thanks, Rick V Report message to a moderator

Re: What amp is this? [message #8916 is a reply to message #8907] Tue, 25 September 2007 06:29   stevem Messages: 4733 Registered: June 2004 Location: NY Senior Member Hi, In all of my 35 years of electronic repair work I have never found a pot to be totaly open unless it had been nearly punched off the amps front panel, in which case then the carbon trace is broken. More likly than not that channel has a dead transistor, and at a cost of about 25 cents each there is no reason to not shot gun that whole board and replace all the transistors in less time than it would take to pull each one and test/replace. Report message to a moderator

The soldering iron is heating up... [message #8919 is a reply to message #8916] Tue, 25 September 2007 10:33   RickV Messages: 6 Registered: September 2007 Location: DFW area Junior Member More great info for an old tube amp guy. The last SS amp I owned was a Vox Royal Guardsman in 1970. I've built a few amp kits (one amp from scratch) and overhauled a few in recent years. Never worked on a SS amp. Thanks again, Rick Report message to a moderator

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