Hello 
I'm looking to obtain one or two PCM1702U chips ideally U-K, after researching I understand they are obsolete. I have looked at obtaining an Denon DCD to strip out the original BB 1702. However I subsequently confirmed they don't actually have 1702, a couple of web sites had suggested that they do Looking at other devices that might have 1702 its clear they are only on top end kit and as such its not cheap to pick up a retro device only to strip out the DAC's...
I'm based in the UK, has anyone had any luck obtaining copied chips? and if so please let me know.. or does anyone have a couple that are known to work?
Clarification regarding quality/fake chips (clearly the chip obsolete, and my assumption is the fake chips are just a copy albeit not quality checked nor will they have been laser etched i.e internal parts that make up the internal circuit and that produce the high level of quality output
Regarding the fitment of the chip.. I need a U (SOP), there are J which are inserted into the boards. Is it possible to source a SOP to DIP for a 20pin U to J (as I understand the wiring is slightly different?!)
Silly Question... but if a DAC is only converting Digital bits into Volts for an OP Amp to process... can i not just bypass the DAC and insert an alternative board.. that can process Data and Clock signals? (its a silly question)
sorry for all the questions
I'm looking to obtain one or two PCM1702U chips ideally U-K, after researching I understand they are obsolete. I have looked at obtaining an Denon DCD to strip out the original BB 1702. However I subsequently confirmed they don't actually have 1702, a couple of web sites had suggested that they do
Looking at other devices that might have 1702 its clear they are only on top end kit and as such its not cheap to pick up a retro device only to strip out the DAC's...I'm based in the UK, has anyone had any luck obtaining copied chips? and if so please let me know.. or does anyone have a couple that are known to work?
Clarification regarding quality/fake chips (clearly the chip obsolete, and my assumption is the fake chips are just a copy albeit not quality checked nor will they have been laser etched i.e internal parts that make up the internal circuit and that produce the high level of quality output
Regarding the fitment of the chip.. I need a U (SOP), there are J which are inserted into the boards. Is it possible to source a SOP to DIP for a 20pin U to J (as I understand the wiring is slightly different?!)
Silly Question... but if a DAC is only converting Digital bits into Volts for an OP Amp to process... can i not just bypass the DAC and insert an alternative board.. that can process Data and Clock signals? (its a silly question)
sorry for all the questions
Your only choice is checking swap meet here, or any other forum market, and ebay (and the likes). There is no guarantee you will receive a working chip for ebay, especially U variation as smd ones when desoldered (with bad skills, as it usually is) are broken.
That chip is current out chip, and signal is transformed to V via resistor and active stage in your case, opamp. Unfortunatelly you cannot replace it with many (pcm63 yes with an adapter board, but it is even rarer chip).
My suggestion is to look at @miro1360 topic with r2r dacs he created, and go for ad1862 as it is on pair quality chip, which is still available to purchase trough legit channel.
That chip is current out chip, and signal is transformed to V via resistor and active stage in your case, opamp. Unfortunatelly you cannot replace it with many (pcm63 yes with an adapter board, but it is even rarer chip).
My suggestion is to look at @miro1360 topic with r2r dacs he created, and go for ad1862 as it is on pair quality chip, which is still available to purchase trough legit channel.
Thanks Brijac, for taking the time to feedback it’s appreciated.
Good point about the U and desoldering I have opted to try out ebay… fingers crossed. However the sellers has sold many IC’s and the feedback looks pretty good. Considering some that I have seen. Here’s the details.. I’ll feedback on the quality once installed…
Good point about the U and desoldering
I have opted to try out ebay… fingers crossed. However the sellers has sold many IC’s and the feedback looks pretty good. Considering some that I have seen. Here’s the details.. I’ll feedback on the quality once installed…Attachments
Hello @ob1234,
I'm in a similar situation than your first post
Any luck on your repair?
The schematic you posted is the same as I have in the service manual of the Yamaha Clavinova CLP-970 digital piano that I'm trying to repair.
I've ordered 2x PCM1702U on aliexpress before Christmas, received them, and now I'm going to have them soldered by a professional (I'm no good in soldering SMDs). Let's hope this solves my problem, as the full motherboard (DM board) is obsolete and not available anymore...
Andrea
I'm in a similar situation than your first post
Any luck on your repair?
The schematic you posted is the same as I have in the service manual of the Yamaha Clavinova CLP-970 digital piano that I'm trying to repair.
I've ordered 2x PCM1702U on aliexpress before Christmas, received them, and now I'm going to have them soldered by a professional (I'm no good in soldering SMDs). Let's hope this solves my problem, as the full motherboard (DM board) is obsolete and not available anymore...
Andrea
How about sourcing the schematic for a lessor Yamaha clavinova CLP, specifically the 840?
No sound from the speakers, a slight hum from the headphone jack. The Aux out jacks work fine as do every other function. Speakers test to have continuity.
No evidence of damaged or burnt up components. I’ve toyed w/getting creative ie bypassing the existing amplifier - the trick has been locating the post volume control output signal
Thnx for reading this far & TIA😊
Tony
No sound from the speakers, a slight hum from the headphone jack. The Aux out jacks work fine as do every other function. Speakers test to have continuity.
No evidence of damaged or burnt up components. I’ve toyed w/getting creative ie bypassing the existing amplifier - the trick has been locating the post volume control output signal
Thnx for reading this far & TIA😊
Tony