Hi. I decided to ask for help. Problem with phono/line input. I have just received it. I decided to use it to listen to audio supplied from an external audio source, in this case a computer. Upon opening it, it appears to bear no signs of repair or alteration, and it is possible that it has never been opened before. The radio works OK. In the tape recorder department, everything also looks good, except for the belts, which have melted after many years. Reading about this model, it is said to have one of the most difficult mechanical systems to service without prior experience with it. But that's a topic for the future. The main problem that arose was the effect of connecting it to an external sound source via a DIN connector. It has a phono/line switch to bypass the phono preamp. Everything seems clear. The sound is clear, but very quiet. After the first connection, the sound was very distorted. After opening, vacuuming, inspecting and reconnecting, the sound appeared. Clear, but quiet. set to 100%. I previously used a Hitachi TRK-8800E boombox in the same configuration and with the source volume set at 20% it was perfect. Same RCA/DIn adapter. I suspect that the cause may be the Phono/Line In switch. Or maybe some capacitor type components, etc.? I would ask someone to review the attached service manual for this model and suggest what I should check. My experience with rtv is not very advanced, but not tragic. I have basic equipment. Multimeter, soldering irons with various blades, etc. With help I am able to diagnose the problem. How about omitting the Phomo phono preamp altogether to simplify the solution to this problem? I'll just use the line input. Ok... Sorry for language errors.I use online translator. Please let me know what to check. I attach the schematic diagram. I can email the full service manual .Thanks and best regards
Hello and welcome I will try to help you as I can.. following the diagram ..from pin 3 of Din1 J1 the signal passes through the double Phono/Aux switch and goes towards the function selector S7 ...Put the initial switch on Aux test if there is continuity from pin 3 of the input Dyn a to the end of the resistor R311 (GREEN section) always leaving the switch on Aux ..at the other end of the resistor (Red section) check if there is continuity up to the selector S4-7... This is to start
I believe, you are feeding the signal to Line-Out terminal of the unit through the DIN cable that you have. I think, the problem is with the DIN cable that you are using. If you are getting vey low volume, in most cases it means that you have connected to the OUT terminals of the DIN socket. Just check if you are getting Line Out from the unit through the same cable while playing the unit. Try to make a DIN to RCA adapter cable yourself using a 5 pin DIN socket or buy a 5 pin DIN cable having 4 RCA connectors (2 in and 2 outs). Please see my post in boomboxery for a similar case, it should solve it: https://boomboxery.com/forum/threads/need-help-for-my-panasonic-rx-5250ls.32470/post-394583
I anticipated that the signals might be on different pins than in the Hitachi I wrote about.That's why I have an adapter like this.Very good suggestion but that's not it.I'll upload a picture of the adapter.I have a thought that maybe the switch has very badly oxidized contacts. Being as careful as possible with the volume levels, I set the switch to Phono.The sound is very loud and very indistinct. Maybe I should start by spraying the switch with something like WD-40 to mechanically and chemically remove the oxidation from the contacts? I will try tomorrow when I can work on it. Of course I will also check what he wrote in the first reply Silver965
Just try with the other two pins that you are not using, or check if it is giving the Line-Out signal through the same pin by playing its radio to another amp or boombox. The low sound that you are hearing is the cross talk signal from Out terminal to the In terminal.
It's getting a bit messy with the online translator. My adapter works fine with the Hitachi TRK-8800E. Comparing the signals of the left and right channels on the pins in its DIN socket are on the other side compared to the DIN socket in Aiwa. Therefore, this adapter DIN x 4 RCA solves the problem without resoldering the wires. Just choose the right plugs. Did I understand you correctly?
Hi out of curiosity I also downloaded the TRK 8800 diagram and the input is reversed with respect to the aiwa .... audio input on 1 and 4
View attachment 40712 That's right.That's why when I hook up the Aiwa using this DIN x 4 RCA adapter from the photo, I use two connectors next to the ones used when hooking up the Hitachi View attachment 40712 Pay no attention to the description on the adapter cable stickers
And also reminded me...Maybe this is a clue ? But I have doubts about it. When I plug in the AC power cable, even when the Power On/Off switch is in the Off position, one of the motors starts working.But I think it is because of the lack of belts in the mechanical section that some switch does not turn on.
Yes. Simply you have to use the right pin. That is why I am saying, just check if you are getting line-out through the pins that you are using currently as Line-in, before doing anything else.
Hi!.The problem is solved.The cause was dirty switches on the board.Mainly the Phono/Line-in switch and DIN socket (sulfides and oxides).Fixing cold solder joints.Also a poor quality 10 meter Jack-RCA cable. But also it turns out that different models of boomboxes need different power of signal delivered to Line-In.In my case I was confused by the comparison to my Hitachi TRK-8800E. Thanks and Greetings
