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No the tuning meters do not move

I’m looking at a BK Precision 4040 sweep generator. Any reason I shouldn’t go with this unit?

Didn’t find any loose wires. I turned L1 screw on end of AM bar that’s mounted on the back panel. Didn’t make it any better. I’ll look at the RF amplifier stage. Thanks again! Should I start pulling capacitors out of the AM section and test them out of circuit? Or, where should I look?

Right on guys! I’m looking at buying a sweep generator. Just not sure what model and specs to buy. Are the cheap new China versions good? Are there any other test equipment I would need for tuner alignments? I’ve been wanting to dive into tuner alignments for years. I’ll look for a loose wire...

Thanks for the info. For test equipment I have an Eico 377 Audio Generator, and a Sony/Tektronix 305 Oscilloscope. Will these two units be suitable for AM alignment? I’ve repaired hundreds of vintage Audio Units including guitar amps, but honestly, Radio is my weakest point in skills.

Yes. I have an antenna connected.

My Fisher RS-2010 has very weak AM tuner. It barely picks up one station. The FM is fine, but has an occasional pop, just one pop at a time . I’ve looked at the schematic and took some voltage readings. IC05 - All pins have the correct voltage except pin 15 is 3.2 mvDC, should be 133 mvDC. And...

Anyone have a service manual for this ? Is there anybody out there? lol

Hello! I have a Lafayette LR-221. I'm in need of a service manual for it. One of the right channel fuses was missing. Also noticed one of the bias adjustment pots (RV501) is broken. Never had this model before, but I hear they sound quite nice. Any help is greatly appreciated. Thanks

Found this. Which should work. The 4th terminal is the center tap. The shaft is too short, so I’d have to use a flat screwdriver to adjust the pitch. I’d still like to find the correct pot with longer , knurled shaft...

Hello. I have an Akai GX-635D reel to reel machine, with a broken pitch control pot. The shaft is broken clean off. This is a 1 kOhm b pot with a center tap. Three terminals on bottom like a standard pot, but with a center tap on top of pot. I’ve looked online and can’t find one like this one...

Before I found the bad capacitor C418, I had already replaced C417 and a few other out of spec caps in that channel. Which brought down the high DC center voltage in that channel. So then, I started puling caps in the opposite channel, and I found C417 was open, No meter reading. Thanks for...

UPDATE: It's fixed! I found a failed capacitor. C418. 220uf - 10v. Luxon brand. Never seen this brand. I researched Luxon brand capacitors, and seems they have a high failure rate. Hit or miss. Anyway, The center voltage is around 50 mvDC per channel. And the bias is set to 15 mvDC per channel...

Bridge mode is off. No change when switching Soft Clipping or LAB input. I started pulling and testing transistors out of circuit, haven't found any bad yet. I also pulled some electrolytic caps and replaced the ones that were out of spec. Now I have -0.082 mvDC center voltage on left channel...

I've been all over this amp again today. Still can't find a faulty component. Does anybody have any advise? I have Good adjustable bias set to 15 mvDC, but has high center voltage at 1.2 VDC.

Hello. I have a NAD 2100 amp that is in Protection mode. The center voltage is at -1.2 VDC for both channels. Shouldn't be no higher than 100 mvDC.... I can adjust the bias in each channel to the specified 15 mvDC. So, seems like the problem is in the protection circuit, but I've yet to find a...

Fixed. I changed out the two switching chips, IC381 & IC382, and that fixed it. My buddy is very happy. I found two NOS TC9163N & TC9164N on that auction site. When the NOS parts dry up, I guess we’ll have boat anchors! lol. Thanks to everyone that chimed in!

Hello all! I have my buddies Luxman R-117 on my bench. When using CD Direct, it sounds great, but if I turn off CD direct, the audio is awful sounding, it’s garbled, and seems to only output the loud peaks of music. Also, I hear CD and FM together. Seems like it’s a problem in the Analog SW...

Cool! It’s good to have guys like him. Sharing knowledge. That’s how I got to where am at. And I’m still learning, and probably always will. I always share knowledge. Even though I don’t much here on AK. Simply because there’s lots of people on here that are super knowledgeable! As for the...

Checking the other channel, it’s at 6 mvDC. So, made me think, if the target is 15 mvDC, and I’m only measuring across one emitter resistor, I should be at 7.5 mvDC. Correct?

Lavane: I seen on another forum that you posted a question about adjusting the DC offset with a DMM. But never got a reply. Did you adjust it with multimeter connected to the speaker terminals? Set to 0.00 dc volts? As for my previous bias adjustment question: I connected my meter across one...

Right on. Yeah, hopefully someone will chime in. I may end up buying a watt meter for this. I find it odd too. I’ve repaired probably hundreds of solid state amps, and never seen this method of bias adjustment. Now some Sansui’s require removing a fuse and insert the meter leads where the fuse...

Thanks for chiming in. Unfortunately, I don’t have a watt meter. And I know most solid state amps bias is measured across the emitter resistors. Speaking on one channel of the amp: Looks likes there’s 6 emitter resistors for one channel. R28 & R29 are .09 ohms - 5 watt. R26, R27, R30, & R31 are...

Hello. I just repaired a Marantz 16 amp. It's up and running fine. But I want to check the bias. The only info in the service manual is 1.25 volts on a 0.22uf capacitor, of the driver board. I want to use my multimeter on the emitter resistors, but I’m not sure if it’s an emitter resistor on...