Rowe Ami R83 125 watt Amp

[Steve.AES]

Hi I hope someone can help me I have an R83 200 play jukebox which has developed a fault since I moved and shipped it to Australia everything appears to work I can select a disc and it plays but I have this issue where is starts playing at a volume quieter than it should and then gets quieter and quieter as the record plays until it is no longer audible apart from what I suspect is mains hum anyone with info that can point me in the right direction? I have looked at the Amp and found a few dry joints which I have resoldered but the issue is still there also found one of the bulbs (DS1) has a broken connection on one side so if anyone can tell me what this is or a replacement I would very much appreciate it. I have parts manual for this system so would appreciate if someone has had this fault and could contact me as I'm  at this stage as apart from going through and replacing all components at a bit of a loss as have no setup to test juke boxes but I do repair computers and peripherals so know my way round a soldering iron and meter etc many thsnks and I hope there is a man that can help 

[ami-man]

Hi Steve,

I know you have contacted me directly so a pair of lamps should be on their way to you shortly.

Regards
Alan

Alan Hood
ami-man
UK

[kb50]

Hi I hope someone can help me I have an R83 200 play jukebox which has developed a fault since I moved and shipped it to Australia everything appears to work I can select a disc and it plays but I have this issue where is starts playing at a volume quieter than it should and then gets quieter and quieter as the record plays until it is no longer audible apart from what I suspect is mains hum anyone with info that can point me in the right direction? I have looked at the Amp and found a few dry joints which I have resoldered but the issue is still there also found one of the bulbs (DS1) has a broken connection on one side so if anyone can tell me what this is or a replacement I would very much appreciate it. I have parts manual for this system so would appreciate if someone has had this fault and could contact me as I'm  at this stage as apart from going through and replacing all components at a bit of a loss as have no setup to test juke boxes but I do repair computers and peripherals so know my way round a soldering iron and meter etc many thsnks and I hope there is a man that can help
[/quote

Worked today on an R83, with the fade in out problems. Just taking it apart 1 of the lamps fell off the board, and the other did when I barely touched it.
These lamps are in series with the volume control pot. They put lamps in because of the fear of stray voltage to the remote volume control. Now was luck the customer had some spare #73 lamps that are used around the edges, to flash with the music etc. Anyhow was able to solder 2 of them back in. Otherwise you will get full volume all the time, which could blow out the amp. Close to ground is zero volume. Anyhow, that however is NOT the total problem. What is the problem, is you need to remove all the plugs on the molex sockets, which requires taking out the large board which is preamp, and equalizer and other functions etc. Then take either needle nose pliers, or better is deoxidizer, or alchol and q tips, and clean all of the pins, on everything. Pull the jumper plug off also which is the interface to the AUX audio board, normally not used. Then remove all the nasty oxidization that are on those pins.
When you re-assemble I put a very very small amount of lube spray, and pull the board in and out, and seat all the plugs several times, to assure solid connections. Then also spray or drops of alchol on all the plugs. Slide them all on serveral times. That takes care of the fading in out, which is mainly the voltage on the volume pot. So spray the volume pot, and/or remote pot also which can drift.

The volume of the amp, is controlled by voltage DC approx 9 volts to 0 volts max audio. Do NOT connect both volume controls at the same time, remove the wire off the terminal strip if your using remote volume. Otherwise you cannot turn the volume all the way down. 10K potentiomer is what AMI uses. Replace it if needed, but use a Linear Pot. (Single) or double if you want to control left and right seperate, such as when you want 2 zone, non stereo. You can switch the MONO STEREO switch to Mono if you want 2 zone amp, and switch E3 leads on the transformer external speaker block around to have 1 zone is jukebox, and 1 zone is remote speakers.

With it working right, play several records, and yank a little on all the cables toward back part of amp. the tonearm cable and the aux cable that goes to the flasher box for the lamps. Then should be able to move the volume level up and down without dropouts or dead spots in the volume.

Remember the volume does not go up or down fast, because the amp was designed with AVC which is there so you don't get thump or click when it starts to play the record the volume slowly comes up. Other than actually blowing out the final transistors, these amps are very solid design.
Do NOT mess with the BIAS controls on the smaller 2 boards, those are factory set to a perfect level. Altering them will cause failure. You can spray them and wiggle a little. They normall are glued in place, and never need adjusting unless you did replace output transistors.
Then only adjust a tiny bit to balance the approx .3 volts positive and negative on each output respectively to be the same approx balanced at 0 volume.
Explained in the manual.