Signal strength meter not working and no stereo reception

[fatblackrug]

I have a Lafayette LR-810 I got for a really good deal and since I have been using it, the signal strength meter has stopped working for FM. It still works fine on AM, just not FM. I also am not getting any FM stereo, no light turning on, and no stereo sound. Any help would be appreciated.

 

[peteCWA]

On the front panel try pushing the Stereo/Mono switch in and out several times to wipe the internal contacts. Those switches were notorious for insulating crud developing on the contacts. If you're receiving a lot of FM stations in a decent listening mode, even if mono, it could be you might have a failure in multiplex section. I don't have the manual or schematic in front of me (it's in the files) so can't give you more specific details.

 

[fatblackrug]

On the front panel try pushing the Stereo/Mono switch in and out several times to wipe the internal contacts. Those switches were notorious for insulating crud developing on the contacts. If you're receiving a lot of FM stations in a decent listening mode, even if mono, it could be you might have a failure in multiplex section. I don't have the manual or schematic in front of me (it's in the files) so can't give you more specific details.

I’ll try that but when I use the receiver in aux or phono Input with an external device, the switch does go from stereo to mono. If it works in that situation could it still be broken for the fm? Anything else I should try? Thanks

 

[waggs098]

I’ll try that but when I use the receiver in aux or phono Input with an external device, the switch does go from stereo to mono. If it works in that situation could it still be broken for the fm? Anything else I should try? Thanks

Is am and fm selected by a rotary switch? Along with all other inputs?

If so that switch i suspect needs cleaned.

 

[tourmax]

This is pretty basic, but what are you using for an fm antenna?

 

[atmasphere]

If you also do not have any inter-station hiss, its likely that an amplifier in the IF (Intermediate Frequency) section has failed.
That would also cause a loss of signal meter level and stereo operation as the signal would be too weak.
The receiver uses two transistors (Q4 and Q5) and two IF amplifier ICs (IC4 and IC1). You can jumper past them (in the case of the transistors from the output of the first ceramic filter to the input of the second; for the ICs from the input of the IC to its output driving the IF transformer) using a 0.01uf cap to see if doing so increases the signal. If it does then the device is bad, if the signal gets weaker the device is good.
As always in stuff this old, electrolytic capacitors are always suspect, such as C44, which is the Vcc+ bypass for the IF section. I'd also check the FM voltage regulator (Q9, 2SC1096), which should be putting out about 13.8V.

 

[peteCWA]

I agree with the previous poster that most likely the problem lies within the RF/IF section of the receiver. Note that the Integrated circuit uPC-555A was notorious for failing in many Lafayette receivers and tuners. It's the last Integrated circuit in the IF section which then feeds the stereo multiplexer. The .01 mfd test across the input and output of each device is a good test for determining if the component is bad.

It also would be helpful to know your trouble shooting skills, test equipment on hand, etc.

I also noticed an error on the schematic and parts pictorial. The 1st RF transistor in the FM section, Q1, is labeled 2SK40. It should be 3SK40. It only took 52 years to notice the error.

 

[geebjen]

I know this was last year, but I'm currently working on a Montgomery Wards Model 150 receiver with no FM output and used atmasphere's recommendation to short the FM IF amplifier input/output with a .01uF cap, because I had a suspicion that amplifier might be bad, and sure enough I could hear the FM radio. So thanks so much for your 1 year old advice, it helped me confirm that my BA402 FM IF Amplifier is bad.