This is the story of course I did the work in my spare time I took about 3 months to get it back in perfect shape and functionality .. here is the Summary At the beginning of the summer I took this Aiwa cs770 (end of May) with the hope of being able to fix it with little work ... Aesthetically in good condition, two knobs are missing and the other two that are there are not his originals .. .the seller assures me that it works but only with the bluetoot and the internal transformer is missing .. Anyway I think I have a 12 v power supply I connect it ... and it doesn't work. First surprise .. it turns on without connecting the power supply ... I open the battery door and find a battery charger for corded telephone and USB socket.
I understand that to a battery installed inside I connect my phone via bluetoot and try a little to hear how it sounds .... the music starts, the ignition and Vumeter LEDs are ok (the vumeter goes to the beat of the music). .... I try to turn up the volume from the knob but nothing happens, I adjust the bass and nothing, I adjust the treble and nothing goes no adjustment .. the volume goes up but only from the phone ... ok I turn off and try to turn on the radio ... the tuning hand moves but no sound .. the cassette door does not open and if I press play or other keys on the cassette, the motor cannot be heard turning ...... Ok ... screwdriver and let's try to open ... Sorpresaaaaa .... over the years I have disassembled and reassembled everything and here for sure something is missing ... you want to adjust ups and downs I said to myself ... Practically ONLY the bluetoot card and the mini amplifier ... the main board with adjustments, amplifier and original radio are completely and unplug ... only connection on the Vumeter and on the ignition switch that turns on only the Bluetoot ... I look at the mechanics of the cassette ... at all the wires cut ... The radio has the connection wire slot empty and no wire starts from the motherboard ... On the Dinamic Super Loudness circuit there is no connection wire .... the same from the power supply board .. no connection all disconnected .... I think but why do such a thing ... cancel all the original electronics and mechanics to use a 5 euro card with an Mp3 sound ..
..I look and regard the main board and I don't see anything burnt, on fire, unsoldered components or burnt, cut, broken tracks ... I don't find anything abnormal on the electronic circuit. Only the loose connections with the wires are missing. ... I cut the wires from the bluetoot circuit .... I disconnect the wires that reach the ignition switch, I disconnect the Vumeter from the bluetoot circuit .... Pliers and screwdriver .. I unscrew the sealing nuts from the potentiometers and loosen the sealing screws I disassemble the White plastic frame with the Radio card attached ... two more screws and remove the aluminum bar with the frequency scale of the Blue radio ... led and surprise ... an integrated by Sharp .... I look at the diagram and try to put the wires with the same original color ..7 wires in all .... I switch to the radio card that has the tuning cord worn out. ..in fact after a while it broke ... I clean the board and glue the ferrite rod of the antenna that moves .... now I let the glue dry on the radio and I dedicate myself to finding the connection points of the Vumeter on the main board ... I balance all the Vumeter wires as shown in the diagram ... Pas I know the radio again and I remove the old connector because I do not have the other connection part ... the holes correspond to a pitch of 2.54 mm but I do not have a single 7-pole connector I am forced to use a 4-pole connector and the other from 3 poles ... the ground falls right in the junction and with a side hole I move the connection (yellow wire) ... perfect I can connect everything on the motherboard ...
Finally I can try to hear the radio I connect two wires to the power supply (Red and Black) and I find the connection points on the main board through the diagram but as soon as the switch is activated, a rustle is heard for a second and then silence ... check the power supply if there is after the switch with the tester and after a couple of ignitions I discover that it is not the switch but the power transistor that does not supply the 9 volts to the circuit ... Q139 2sc1846 ... I don't have at home a substitute unsalted it from the circuit and I try with an LM 7808 an 8 volt voltage regulator .. I connect it with three flying wires just to see if by supplying power to the rest of the circuit you hear something ..... Finally I hear the radio but only on one channel ... and already something. I check with the tester if the 8 volt power supply is stable and I touch the 7808 with my fingers to feel if it heats up ... the voltage has dropped a little to 7.5 and the heat rises slightly ... The channel that is not heard makes background rustle I assume that it is not the output amplifier IC105 AN7146 ... I touch the fin of the amplifier and it is not hot ... I shift the balance only on the channel concerned (which is not heard) with my fingers touch the input pins of the audio amplifier and I have confirmation from the noise that he is not the culprit ... I check the two integrated ic101 and ic102 two preamps LA3161 used for the Phono / Line input and the other for the Head of the tape ... the values that I measure even if a little lower correspond to the diagram ... this is not the problem ... I move to measure and compare the pins of the two IC 103 and 104 LM1111C Dolby NR .... Found IC103 with out-of-scale measurements ... many pins give 7.5 volts which does not correspond to each other's pins .... I dissold it ... Now without IC103 I measure the supply volts and I no longer have 7,5Volt but 8 Volt as in output from the voltage regulator ....
In the meantime LM1111C arrives, I replace the 7808 regulator with a 7809 to have the 9 volts as shown in the diagram ... and I manage to mount it on the main board in place of the old power transistor by making a hole on the ground for the central foot ... A at this point I began to draw the scheme to reconstruct a missing original circuit where the speakers and microphones were connected ... F Relay cb ...When I finished with this circuit I started with DSL (Dynamic Super Loudness). As you can see from the photos on this circuit there are some components that are missing in this model but are mounted in the Aiwa J77 MkII .... I start to check the potentiometer for the bass volume that does not seem to work by measuring it with the tester
After cleaning and a small fold on the contact strips I put it back together and it seems to work by measuring the resistance variation ... I start connecting the audio and power wires on the DSL card and after a short test with the radio I can say that it is ok and finally I reassemble it ..... But I have not finished yet now I have all the mechanics of the tape to clean and reconnect .. I weld the first three wires that are mounted on the switch in front ... then I have to get to the wires cut inside and I touch disassemble ... I reconnect the switches and also the heads ...
cripes this really is a labour of love, good luck dude, i gave away a mint modded 770 and i don't think they appreciated it and it was sold....should have sent it to you dude
Oh, My! This is one impressive Resurrection!!! Boys at boomboxery.com must have this also! I love AIWA bboxes, methinks these are the best-looking boxes ever made... shame on me that I never had one: a bit of stuck with National monos and 'Black Beauties' But going through @Silver965 resto-efforts make me feel as if I Belong to The Club AWESOME!!! and PLEASE share more photos of the end-result!
Thanks guys .... Radio Raheem I don't have many boomboxes in all 4 Aiwa of which 3 are under restoration and I hope to publish again ... Jorge this is finished .. it is not aesthetically perfect but it gives me a lot of satisfaction .. I like them also the 770 and 880 series
The last switch is that of the break ... Now the problems begin ... I clean the mechanics from the old lubricating grease and reassemble ... but I have made some mistakes that have made me waste time and that those who come across again I would not Also because every time you have to disassemble and reassemble the mechanics .. the photos explain well ... The position of the springs and gears ... After many hours of testing and trying again I succeeded ..... I would say that from the beginning so far some wire has been added
I do some tests with the cassette ... mechanically and perfect all the functions are fine including the hitchhiking at the end of the stroke ... I adjust the engine speed that seems faster to me (the adjustment is on the back of the engine) but audio and disappointing changing the wires on the head I noticed the wear it has ... but I wanted to try ... I can't find a fixed point with the azimuth and so I decide to change it ... I have an Aiwa CA w45 for spare parts and I try to change the head with one of this ... It does not improve much but I can find a certain stability in the azimuth adjustment ... but after several tests I am convinced that it is still not good .. I take out another waste that I have from time a double tape of the Pioneer CT-1180W and take out one head The Pioneer head is not round like the two Aiwa and with larger and longer reading strips ... it fits perfectly and finally I have good audio and optimal azimuth adjustment ... with the new integrated LM1111C just replaced I have both channels ... Ok the electronic part .. Ok the mechanical part .... I reassemble everything I wash the rear part I have to fix two cracks .. one at the bottom and one at the top on the same right side
I start to scrape the surface where to apply the glue inside I personally used a mini drill but it can also be done with glass paper ... I used two-component glue that at a reaction time of about ten minutes before starting to harden ... The upper side once put the glue even inside the crack I kept it in place with adhesive tape .. the glue coming out on the outside must be cleaned immediately otherwise it remains visible ... Same thing done on the crack on the bottom ... internal scraping and glue in abundance .... Since I was with the glue at hand I also glued a holding pin for the internal microphone made with a toothpick ... the last two photos show the result final gluing. The upper part is not very visible while the lower part is more noticeable from below the radio
Well now I can show you how I fixed the speakers ... With water and vinyl glue .... or how I used the transformer of the Pioneer CT-1180W ... Or how I modified the power supply unit to adapt it to the transformer ... (The transformer delivers 18 Volts alternating which simply straightened in dc becomes about 21 Volts) ... restored the tuning cord. Look at the photos As I put it before it worked but on the contrary (it must be on the outside) .. Etc Etc ....
Ok last photos before closing the lid ... The music box-style cassette door release mechanism has replaced the lanyard .... redone the hook for the slide switch for recording .... Mechanics overview with the Pioneer head
Excellent thread and Excellent work. I look foward to the next one you restore good to see more on Boomboxes on the forum.
This is the actual result ... Knobs absent at the beginning of this tred I borrowed from another model I have ... Listening to music is a pleasure ... bass adjustment is fine Dolby is ok .. The cassette is good for both listening and recording. It can record from the radio ... from the internal Microphones ... from the input line ... and directly from the head of a turntable ... On the back external microphone inputs ... a Line Out output and also two sockets for external speakers. ..The Battery Compartment is in excellent condition, no rust ..On the side the socket for the power supply and plug for external power supply
I'm surfing the internet a bit these days looking for suitable knobs but I haven't found anything ... so I said to myself let's try to recreate the knob .... I can't use a 3D printer because I don't have one available and I don't I know how to use it ... so how do you do it ?? I dedicated myself to molding ... I created a rubber mold from an original knob ...With two plastic cups for coffee ... it came out perfect ... (I must say, however, that before the rubber I used a silicone paste to try but I could not get a good result) ... Made the mold I used a two-component resin in this case transparent ... this is the result ...
