Recent content by fred soop

Today appeared to be "Dave Brubeck" day. I heard Time Out 3 times in about 15 minutes. Martin Logan has a good surround system but it needs properly recorded music to work as intended.

With classical music, a soloist is usually front and center. Violins are more toward the left with larger strings to the right. But horns and woodwinds are few in number and usually close to center, behind the strings. Percussion will be in back. The occasional harp seems to be to the left.

Yes, the "K" is Kloss. L and H were Malcom Low and J Anton Hofmann. The Advents were allegedly the best selling speakers of all time but for Kloss, they were only to provide income to finance his research into video projection. He later founded Cambridge Soundworks.

The transformer can produce a hum mechanically from vibration of the core. I have this on a Citation 24 (same as 22 except lower power and only one transformer). The fix is to remount the transformers on longer screws with flat washers and the transformer flanges trapped between a pair of rubber...

Could be an intermittent open circuit that is sensitive to being heated. Maybe try to wiggle various parts and see if that will cause it to start, or quit.

Much of my work on 43453K was replacement of then 48 year old electrolytic capacitors. There were a number of minor changes, some electronic, some physical layout. But there were few changes in actual circuitry other than the bias network in the power amplifiers. The IF is powered from the front...

There were 2 600-T projects. The first was s/n 434535K which was mostly a refurbish done around 2014. The second was s/n 38215G around 3-4 years ago and was a total rebuild other than FM IF and Multiplex with completely updated circuits. Power supply is close to original. The power amplifier is...

Right behind you Larry.

The jumpers with corrosion are to bypass the reverb loop. I did a rather complete restoration of a 600T. Serial number is 43453K. You should be able to search for the posts (around 2014) by the serial number. ALL electrolytic capacitors should be replaced as they are almost 60 years old...

Google Tektronix, go to Support. Scroll down to Learning Center and Resources. More information than you will ever be able to use.

The main tuning capacitor is closer to fully meshed at the lower end of the dial. Look carefully at the capacitor plates to see if any may be shorting. Maybe surrounding heat is distorting one or more plates to the point of shorting.

Is the noise still present if the stylus is not in contact with a record? If so, then the problem is probably not acoustic feedback.

There is an eBay seller "JoeOldAudio" that has a lot of stuff, probably more than he can reasonably list. Might do a "contact seller" and ask. Another possibility, but a long shot, would be Mark Oppat.

The diodes have to be disconnected before checking continuity or you won't really know what you are looking at. I assume you disconnected the speakers, but that large coupling capacitor will show continuity from the very low meter current for a long time before the capacitor charges enough to...

Connections are relatively unchanged. Big changes are R25, R27, R29, R31 (numbers from my schematic) and their counterparts in the other 3 locations. Values of R21 and R23 (and their counterparts) are slightly different but not critical. My 600-T has 35144 transistors in all 8 positions, again...