To hopefully improve performance and longevity, I am going to attempt a full re-cap of the D8443. Where do you all get your electrolytic capacitors?
Time to re-cap the "D"
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Does anyone have a list of the eletrolytics and their values needed for this box? I have the service manual but it is not clear. I am compiling a list in the meantime, going through the service manual schematics.
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caution
Member (SA)
Electrolytics have the capacitance and working voltage printed on them. The service manual doesn't list their voltages, and which ones are electrolytic that's obvious to me, so just write down what you see on the caps on your board and order those. Looking at a picture of the D8443 mainboard, it looks like there's only 30-35 of them, pretty manageable. The voltage can be higher if you can't find the exact same value, as long as it's not less.
caution
Member (SA)
I took another look and see how the coding works. I found 42 caps.
Tuner:
2207, 2208, 2219, 2794: 0.47µF 10V
2202: 2.2µF 10V
2105: 10µF 10V
2123, 2130: 33µF 10V
2121: 33µF 16V
2793: 47µF 10V
2787: 47µF 16V
2791: 100µF 10V
2790: 470µF 10V
2788: 470µF 16V
2785: 1000µF 25V
2786: 2200µF 25V
Amp:
2502, 2521, 2554, 2602, 2621: 0.47µF 10V
2506, 2520, 2535, 2606, 2620, 2635, 2708, 2805, 2808: 1µF 10V
2524, 2624: 2.2µF 10V
2525, 2531, 2625, 2631: 4.7µF 10V
2541, 2550: 10µF 10V
2702, 2802: 22µF 10V
2728: 22µF 35V
2504, 2555, 2604: 47µF 10V
2537, 2538, 2637, 2638*, 2709, 2711, 2736: 100µF 10V
2534, 2552: 100µF 16V
2558, 2610: 220µF 10V
2540, 2640: 220µF 16V
2556: 1000µF 16V
* 2638 has no voltage defined on the schematic, but likely 10V given its place in the circuit. Check cap on board to confirm
Tuner:
2207, 2208, 2219, 2794: 0.47µF 10V
2202: 2.2µF 10V
2105: 10µF 10V
2123, 2130: 33µF 10V
2121: 33µF 16V
2793: 47µF 10V
2787: 47µF 16V
2791: 100µF 10V
2790: 470µF 10V
2788: 470µF 16V
2785: 1000µF 25V
2786: 2200µF 25V
Amp:
2502, 2521, 2554, 2602, 2621: 0.47µF 10V
2506, 2520, 2535, 2606, 2620, 2635, 2708, 2805, 2808: 1µF 10V
2524, 2624: 2.2µF 10V
2525, 2531, 2625, 2631: 4.7µF 10V
2541, 2550: 10µF 10V
2702, 2802: 22µF 10V
2728: 22µF 35V
2504, 2555, 2604: 47µF 10V
2537, 2538, 2637, 2638*, 2709, 2711, 2736: 100µF 10V
2534, 2552: 100µF 16V
2558, 2610: 220µF 10V
2540, 2640: 220µF 16V
2556: 1000µF 16V
* 2638 has no voltage defined on the schematic, but likely 10V given its place in the circuit. Check cap on board to confirm
Parts identified and ordered from Digi-Key. I counted 59 electrolytics and ordered the correct capacitance and tried to match voltage and exceeded it if the match was not available.
| Value | Count | Substitution | Qty Ordered | Cat No. | |
| 1000uF 10V | 1 | Sub 16V | See Below | 493-13397-ND UKL1C102KHD Nichicon CAP ALUM 1000UF 10% 16V RADIAL | $ 4.40 |
| 1000uF 16V | 2 | 4 | |||
| 1000uF 25V | 1 | 2 | 493-13399-ND UKL1E102KHD Nichicon CAP ALUM 1000UF 10% 25V RADIAL | $ 3.06 | |
| 100uF 10V | 7 | 10 | 493-15343-ND UKL1A101KEDANA Nichicon CAP ALUM 100UF 10% 10V RADIAL | $ 3.08 | |
| 100uF 16V | 2 | 5 | 493-10975-1-ND UFW1C101MDD1TD Nichicon CAP ALUM 100UF 20% 16V RADIAL | $ 1.45 | |
| 10uF 10V | 3 | 5 | 1189-4041-ND 10MS510MEFC4X5 Rubycon CAP ALUM 10UF 20% 10V RADIAL | $ 1.45 | |
| 1uF 10V | 9 | Sub 50V | 12 | 493-14955-ND UDB1H010MPM Nichicon CAP ALUM 1UF 20% 50V RADIAL | $ 6.71 |
| 2200uF 25V | 1 | 2 | 493-10648-ND UKT1E222MHD Nichicon CAP ALUM 2200UF 20% 25V RADIAL | $ 4.64 | |
| 220uF 10V | 2 | 5 | 493-15116-ND UFW1A221MED Nichicon CAP ALUM 220UF 20% 10V RADIAL | $ 1.80 | |
| 220uF 16V | 2 | 5 | 493-10979-1-ND UFW1C221MED1TD Nichicon CAP ALUM 220UF 20% 16V RADIAL | $ 1.70 | |
| 22uF 10V | 2 | 4 | 493-15012-ND UES1A220MDM Nichicon CAP ALUM 22UF 20% 10V RADIAL | $ 3.93 | |
| 22uF 35V | 1 | 2 | 493-4664-1-ND UKA1V220MDD1TD Nichicon CAP ALUM 22UF 20% 35V RADIAL | $ 1.00 | |
| 2.2uF 10V | 3 | Sub 35V | 6 | 493-15889-ND UPX1V2R2MPD Nichicon CAP ALUM 2.2UF 20% 35V RADIAL | $ 5.16 |
| 33uF 10V | 2 | 4 | 493-4633-1-ND UKA1A330MDD1TD Nichicon CAP ALUM 33UF 20% 10V RADIAL | $ 2.00 | |
| 33uF 16V | 1 | 2 | 493-16299-ND UFG1C330MDM Nichicon CAP ALUM 33UF 20% 16V RADIAL | $ 0.80 | |
| 470uF 10V | 1 | 2 | 493-10972-1-ND UFW1A471MED1TD Nichicon CAP ALUM 470UF 20% 10V RADIAL | $ 0.68 | |
| 470uF 16V | 1 | 2 | 493-4493-1-ND UBT1C471MPD1TD Nichicon CAP ALUM 470UF 20% 16V RADIAL | $ 1.90 | |
| 47uF 10V | 3 | 6 | 493-10943-1-ND UFG1A470MDM1TD Nichicon CAP ALUM 47UF 20% 10V RADIAL | $ 2.16 | |
| 47uF 16V | 2 | 4 | 493-16221-ND UFG1C470MEM Nichicon CAP ALUM 47UF 20% 16V RADIAL | $ 2.16 | |
| 4.7uF 10V | 4 | 8 | 493-15031-ND UES1E4R7MDM Nichicon CAP ALUM 4.7UF 20% 25V RADIAL | $ 3.92 | |
| .47uF 10V | 9 | Sub 50V | 50 | 493-11361-1-ND UPW1HR47MDD1TD Nichicon CAP ALUM 0.47UF 20% 50V RADIAL | $ 8.05 |
Where does the 1000uf @10V cap go? Seems like a lot of capacitance for such low voltage. Also honestly there’s no reason to buy so many caps with same capacitance but different voltages. The manufacturer does that to save money but you’re better off buying the higher voltage cap in higher quantities to take advantage of the price break. Older caps were larger for the voltage. Better manufacturing technology allow caps with same voltage to be smaller than their vintage counterparts. Therefore if you have a 16uf cap in 6.3, 10, 16, and 25v varieties, as long as they fit, just get all 25v. Anyway that’s what I do, and it’s worked well.
Tinman
Member (SA)
I agree with SD.
I usually buy 50v in everything under 100uf since there really isn't that much size difference.
When I'm installing them, I leave them in piles from smallest to largest and just have to verify the capacitance which makes it faster and easier.
Something to keep in mind for your next recapping.
Don't forget about tweeter caps unless that box uses piezos.
I buy polypropylene or polyester.
You can use electrolytic caps but you have to make sure they're non/bi polar.
I usually buy 50v in everything under 100uf since there really isn't that much size difference.
When I'm installing them, I leave them in piles from smallest to largest and just have to verify the capacitance which makes it faster and easier.
Something to keep in mind for your next recapping.
Don't forget about tweeter caps unless that box uses piezos.
I buy polypropylene or polyester.
You can use electrolytic caps but you have to make sure they're non/bi polar.
I considered doing that but decided it didn't matter this time. If i start needing these parts in bulk I will definitely get the higher voltages.
Digi-key didn't waste time. Also very well packaged! You never get this level of protection from amazon
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The recap is mostly done. The only place that has not been recapped is the control board. I have replaced 53 eletrolytic capacitors so far. The operation was a success, the patient is ambulatory: the radio still works decently, and the noise on the cassette preamp is significantly lower, but still noticeably higher relative to radio mode. I am still using the external mic inputs for the Bluetooth which works in radio/on position, I have to set the band selector between detents to silence the tuner to hear the Bluetooth. Next step is to get the audio cleaned up in general. There is AC hum that all cheap radios have when plugged in, but dammit, I want it gone.
Many people have that hum with bluetooth receivers. If you install a DC
C converter, such as those mornsun chips, it'll most likely go away. Mic inputs are not the best place to tap into. Those inputs are intended for low signal levels and highly amplified, yep noise too. The choice of location where you tap into is going to have a significant effect on noise and performance. According to the schematic, BU-5 and BU-6 are probably the best spots, but I don't know what jacks those represents, are they the mic inputs or line input?
C converter, such as those mornsun chips, it'll most likely go away. Mic inputs are not the best place to tap into. Those inputs are intended for low signal levels and highly amplified, yep noise too. The choice of location where you tap into is going to have a significant effect on noise and performance. According to the schematic, BU-5 and BU-6 are probably the best spots, but I don't know what jacks those represents, are they the mic inputs or line input?
Many people have that hum with bluetooth receivers. If you install a DC
BU 5 and 6 are liine out, BU 1 and 2 are Line in. The Line In jacks are not working well, even after replacing the capacitors. The line level input is way too quiet and covered with noise, even with the BT device or any other line level signal at full blast. There is something wrong with that area. Don't know what is going on there. It could be a defective jack, selector switch, bad connection of the "jack comb" to board, or some other defect along the signal path. The external mic inputs don't sound bad to my ears with 2/3 volume (input gain) from the BT module, but likely not ideal. I know traditionally this would be an undesirable application, but on this particular unit it's the best I can do until I find another way to get the stereo BT signal into the amp. I am wondering if I could insert a toggle switch between radio AF output and its amp input and connect BT to that and forget about the cruddy side of the amp board. I could also pursue fixing the line in and tie in there properly. I have also though about replacing the amp entirely, which turns most of the recapping exercise into an expensive soldering practicum.
BU-1 & BU-2 signal goes through 3512 & 3612 820k resistors, making the input impedance a whopping 820k at the minimum. That seems really high, especially for signals that doesn't go directly to an opamp. Normally I see something like 10k or 20k on line input impedance so this is really high. You maybe can experiment and try replacing those with lower ohm resistors. Or try this: Put the set into line-in mode but inject your input into the line-out jack instead. That gives a straight shot to the amp and bypasses the ALC circuit as well as the high impedance line-in circuit.
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