While price of SONY CX20084 speed regulator CHIP soar up, there are more and more fake CX20084 chips flooded on the market, I was thinking about making an authenticator to distinguish genuine or fake chip fast and effectively long time ago. Recently, I completed two authenticators, here it is: Choose a cheap (poor cosmetic condition) SONY DD Walkman and confirm which is using CX20084 as speed regulator chip, such as: WM-DD1 (same as WM-DD10), WM-DD11, WM- DDII, WM-DDIII, WM-D3, etc. You also need following accessories (1) One piece - Test Socket - SOP16 16-pin, pin pitch 1.27mm, chip body width 5.4mm (209mil) IC test socket (re-programming socket) , see pictures: (2) Two pieces - FFC/FPC 1.25mm pitch flexible flat cable 8pin reverse direction, length 300mm~450mm, see picture (3) One piece - SOP16 to DIP16 single-sided adapter board 1.27mm pitch, see picture. The total cost including international postage will not exceed USD30.00 if you are choosing to buy from China. Before you are doing the modification, you need to confirm the selected Walkman is fully operational and functional as intended, if not, you need to repair it first, such as replacing center gear, rubber capstan ring, belt, electrolytic capacitor, cleaned potentiometer for headphone volume control etc. Then start the following modification steps: Disassemble the main board of the DD Walkman; de-solder the CX20084 chip on board. If you are using SONY WM-DD11, replace the 4 SMD electrolytic capacitors around CX20084 with 3216-18 A type (4.7uf 35V, 10uf 25V) and 3528-21 B type (220uf 10V x2) tantalum capacitors (see pictures), to reduce the height of the capacitors and the FPC cable, otherwise the FPC cable will be broken easily if twisted too much. Solder the 9-16 pins first (see the picture), and be sure to test whether each wire is connected after completion, and mark 9-16 at the end of cable correctly (both sides). Over the 9-16 FPC cable, solder the 1-8 cable, please remember two FPC cables should be paralleled and neatly overlapped. After the soldering is completed, test whether each line is connected, and mark 1- 8 at the end of cable correctly (both sides). Use sticky tapes to protect the soldering position, and strength cable ends. If you are using the WM-DD11 model, curve the FPC cable 90 degrees in the opposite direction and fix it with double-sided taps, pass the other end of the FPC cables through the edge of battery compartment to the outside of the aluminum casing (see picture). If you are using WM-D3, DD3 etc., just pass the FPC cables along the edge of the motherboard to the outside of the aluminum casing (see picture). Solder the SOP16 test socket board to the SOP16 to DIP16 adapter board, pay attention to the asymmetry of the pin width of the adapter board and the socket, you may need to force it out to insert the adapter board, it may cause poor contact between the test socket board and the pins, test and re-solder all points (not easy). Solder the FPC cables to the adapter board according to 1-8, 9-16 markings, test whether each points is connected, from DD mainboard to test socket, to check if there is any short-circuited, the order of the pins is correct. Use sticky tapes to cover and protect the soldering position and cable ends. If you are thinking about adjusting the tape speed outside the casing, you need to adjust the resistance of RV601 on the DD mainboard to the maximum value, and then solder a 300KΩ resistor + 1MΩ adjustable resistor (Variable Resistance) between pins 4 and 5 of the test socket. I modified two Walkmans for testing, one is WM-DD11, another is WM-D3, the advantage of using SONY WM-D3 as a testing tool, and you can distinguish: good, busted and fake CX20084, since WM-D3 has LED power display. WM-DD11 cannot distinguish the busted chips (burned). Please prepare a test tape before you doing any test, ordinary music tapes are also acceptable. Don't use your valuable collection as a test tape, since the WM-D3 may erase your tape if you pressed wrong button. The followings are the test results with WM-D3 and WM-DD11 (the ambient temperature is 26~27℃), plug-in power with on/off switch. (1) If you fitted a CX20084 into the test socket, turn plug-in power on, then press PLAY button, WM-D3 works properly (Pause is off), and you are able to continuously playback tapes for over 10 minutes, the CX20084 chip does not heat up (even a little), this indicates the chip is the genuine SONY part, Congratulations! (2) If the CX20084 chip heats up slowly, but the playback is normal, the chip may be an imitation – A third party parts, which may easily get damaged, so be careful. (3) If a CX20084 is fitted in the test socket, turn plug-in power on, and there is no button pressed down, but you can hear the WM-D3 motor rotates immediately and fast, (WM-DD11 needs to press the PLAY button to rotate) after you press the PLAY button, the WM-D3 transports the tape unsteadily, the music sound changes, and the wow & flutter increases significantly; if you are using WM-DD11, tape speed reaches between 5000Hz and 6000Hz (almost 2 times faster and speed adjustable resistor has no effect at all), or music plays like an allegro and after 10~15 seconds, music suddenly stops (or muting repeatedly for WM-DD11, but motor keeps on rotating fast) no matter which machine is used for testing, the CX20084 chip will heat up quickly and rise to 45~55℃ within 1 minute, these symptoms indicate the chip is a FAKE one. (4) If the CX20084 is fitted in the test socket, plug-in power on and no button is pressed, the motor does not rotate, but the LED power BATT light of the WM-D3 is on. After you press the PLAY button, motor does not rotate, and the chip heats up rapidly, and will rise to 40~45℃ within 1 minute, indicating the chip is busted or burnt. Since fake chips have many types, the symptoms may vary. Here are some test chips for your reference:
Hello and welcome ... All this and a great job thank you for posting it here ... just the fact of creating an external support for the chip is great ...
Oh wow. Glad I saw this thread as there has been recent comment on Tapeheads about fake CX20084 chips but the ones I purchased several years ago are the ones that "can be used". Was about to take a genuine CX20084 out of an old but working DDII to resolve a problematic speed issue with a nice 5 digit SN D6C I acquired for parts. Seems these 815N53F ones are not around any more either.
Just found this amazing item on AliExpress. Check it out! $5.00 | 1pcs CX20084 SOP16 5.2MM [SMD] https://a.aliexpress.com/_m0W6CEG This is the only one I could find on the internet on my phone. Is this any good?
Well the ones I bought years ago were 815N53F which are replicas but I believe can be used in place of the genuine CX20084. I'm about to find out. These are the expensive ones on the Ali site at A$126 on my link. At that price you'd be expecting they're genuine CX20084 replicas. I doubt the ones under $10 ea would be anything other than a pocket warmer. I suppose if you've got a test rig set up it won't cost much to buy and test one and some of the others listed.
Well the cheap "CX20084" arrived quickly at least but as expected it bears the ID number shown here as a fake 106N53F. You don't get that piece of information without seeing it close up. It's not in the description on AliExpress. Will still test it but not expecting it to be a functional imitation of the original CX20084 chip. But on the plus side the test rig we are using on a DDII has confirmed operation with the batch of replica IC's I bought several years ago. These were all marked SONY and had ID 815N53F. Now these are on the AliExpress site too but at $A130 plus. You'd expect that they would be usable replacements but I'm not going spend that much to find out. The ones I have were bought on eBay years ago and I can't recall the seller name.
