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Discussion Starter #1
Got one of these coming to replace my antique Alpine 7915M. Has anybody successfully modified the tuner to receive worldwide FM frequencies?
I found this guide for a McIntosh unit which should be made by clarion so in principal it should be similar. Finding a clarion unit to swap the tuners over is next to impossible in the UK as they are very rare and i'm not going to use a band expander as it degrades the quality too much.

I found some similar info to the above on some russian sites that suggest losing 1-1.5 turns from the coil would alter the band range to approximately the right point.

This is the 9255 tuner.


Apparently its the same mod on an HX-D1.
 

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Discussion Starter #3
I only live on the border so presently my alpine picks up radio 2 perfectly, and i reckon the addzest would too. (but that would be all it picks up as its limited to 90MHz) Only reason i want to convert the tuner is because i'm a bit OCD about such things and i'd like it if i was able to use the radio to pick up local stations to check on traffic reports. (which I'll admit doesn't require supreme SQ)
 

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Yea i was only joking, if you contact Yuri ( either on here or TA ) he might be able to help ( i belive he is a bit of a guru on these, Other than that i'm afraid i cant really help sorry
 

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Try Gordon @ Genesis/amp doctor too. He has sexually explicit MX406 content on his desk and car.
 

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Discussion Starter #6
Cheers for the advice, will get on it once the unit arrives. Would be easy if it were as simple as adjusting some pots or you could buy the tuner module from pacparts etc.
 

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Discussion Starter #8
Well it turned up today and i can say that i am very impressed with it. As much as I liked my alpine, it makes the alpine feel a bit cheap and clunky. (not to mention the fact that it actually works) CD mech was a bit squeaky so i took it apart and gave it a quick clean up and re-greased the gears. Much quieter now, and happily playing away on my test bench without an issue. Radio is japanese frequencies as expected. It also came with everything from cage to plastic surround.




One thing that caught my eye whilst i had it apart was that it has a denon processor. I thought that only the EX/EXL models had that. (The pictures I've got of the inside of an EXL are identical in every way, I cannot see a single difference anywhere)
 

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Discussion Starter #10
Display colour is changed by pressing and holding disp and pressing the 1 button (on the 6 radio presets, pressing 5 whilst holding disp turns the beep on and off too.) Got it fitted in the car this morning looks quite tidy and sounds fabulous.

 

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Discussion Starter #12
Ecstatic with it. It has managed to exceed my expectations. I just wanted a unit that worked with the clarion changer that i had in the car and didn't have noise issues or remote problems. The old alpine picked up noise from the climate control stepper motors and the CD-mech also introduced some noise from the spindle motor. It had an intermittent remote/antenna output so i had to use a separate switch to sort that. It was also quite fussy about the brand of CD-R's used for home-made compilations.

I've turned the gain on my antique alpine amps right down to minimum and it's still a heck of a lot louder compared to the 7915. I suppose that's what you get moving from 0.5V preout to 4V. (amps are a 3553 and a 3566, which are fed though a 3672 active crossover)
 

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Discussion Starter #14
Nope I've left it for now and I'll see how it goes for a while. I'd like to get hold of the service manual before i consider tweaking it. I noticed a pair of solder pads inside the unit marked USA which i'd guess are for surface mount resistors. Pin 77 on the main IC is supposed to be for switching the tuner destination, but from the picture i took of the mainboard, i can't see a connection at that pin.
 

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Discussion Starter #15
Found this video of an Addzest tuning to worldwide frequencies and also found some info on the conversion process albeit in russian.
DRX9255 FM - YouTube

Here's the translated text although some words remain foreign:

Here is the article is like a man tinkering with the radio:

That allowance, on which I remade, because there is clearly written that can be distributed freely on the territory of Russia, etc. publish the name of the author, but my amendment, which was skated on the 2 copies DRH9255, so that they consider the regularity and advise you to use!
Inaccuracies in the article, and add / correct a signed text of the valves, so you must first COMPLETELY Read the full article, get to the core and get down to business!

As I rewrote the tuner in the DRX9255. Reporting manual.

(C) Docent 3D
Andrew, Peter


The following information is a summary of my research on "Remaking FM-tuner Addzest DRX9255 on the European frequency range," and allowed to free spread throughout Russia, CIS countries, as well as Europe, America and others ....


To start a small introduction. The basis for the alteration of operations was the information kindly provided by Alexander Yureninym (Alex), as well as material from the book by Anatoly Shishatova (ZHSH) "at the Concert Hall koloesah." Ea is a special thank you to them.

A bit of theory to help understand the process of remaking. FM tuner with DRX9255 built under the scheme with the local oscillator and frequency synthesizer. The idea of ??this design is that the LO signal is divided by frequency and compared with the reference signal frequency and phase. The reference signal is generated separately, in the management of the scheme and the step is in the relevant frequency range. In our case it is 0.05 MHz. After comparison, the control signal is generated LO frequency, which changes the latter so that it was equal to the net step frequencies multiplied by a factor of division. Thus, fine tuning is achieved to the desired frequency oscillator. LO frequency control, and other tunable LC-circuits arranged with varicaps included in this circuit.

Now, how and what was done, and how can you do if you decide to rework.

The stage of disassembly.
- Take out Addzest RDX9255 of the car.
- Remove the top cover.
- Remove the bottom cover.
- Remove the front panel.
- Turn off and remove the vehicles.
- Turn off and put off to the side of her hair off RCA-plugs.
- Unscrew all the screws that hold the rear wall of the housing unit with everything else.
- Unsolder the wall from the board (two points) and remove it.
- Carefully remove the lid-screen tuner. It is attached to the snap-ledges. Two left and right.

Stage alteration management system
- Put the unit upside down and "face" of his own. In the upper right corner of the board we find two pairs of pads, next to which it is written «Japan» and «USA». SMD-resistor is zero resistance to solder a pair of contacts «Japan» a couple of «USA». Everything. Now, the control system switched to the Euro-American bands. This means that the display will reflect the figures familiar to us from 87.5 to 108MHz, and the frequency synthesizer is to compare the frequency of oscillator, taking into account the fact that the oscillator has been tuned to other frequencies (for our range).

- To change the pitch of the tuner of American 200kHz to 50kHz for our holding down the «BAND» double-click on the "<<"

- Switch to manual / automatic setting by pressing and holding the button «BAND»

Stage of alteration itself tuner.
- If you look at the back of the unit, we will see a lot of on-board tuner coils and other detalyushek Lilliputian size. As it is not terrible, but some of them we have to vypayat and subjected to modification. To do this, always need a low-power (preferably not on the 220, but with the step-down transformer), a small soldering iron, a magnifying glass and good light source.
- So, we place the device flat on the main board down. We are looking at him from behind. Standing vertically on board tuner, we are interested in three coils (TOP - BLACK, WHITE MEDIUM, LOWER GREEN BEZKARKASNAYA (looks like a very large, spiral).
They are strictly on a vertical axis passing through the center of the board tuner. The first coil on top - odnoobmotochnaya. This oscillator circuit coil. Under it a trimmer toli, toli trimmer capacitor - to us he was not interested. Another double-wound coil is below - it's interstage transformer with tunable LC-circuit at one of its windings. Still lower is a frameless coil of the input circuit of the tunable radio frequency FM tuner.

Alteration of LO.
- Put a muzzle device in place and turn it. In Tuner mode are connecting a voltmeter to the 15th pin connector tuner, designated VT. According to it, the tuner receives the signal tuning circuits with a frequency synthesizer circuit. Regardless of the selected frequency in this output will be about 7volt. Though when all is well, there must be a minimum of 2.1 (87.5 MHz) to 6Volt (108MHz). But we switched to a different synth mode, and the oscillator is still running in the old format and can not be reconstructed. Accordingly, the frequency synthesizer provides the best possible control signal to the LC-circuits varicaps tuner. In order to outline the LO can be reconstructed at high frequencies, it is necessary to reduce the inductance of the coil. Fed to it. It turns 4.5. Wind off one or two turns (do not cut off the excess wire!!!) And solder the coil on the back of the card. So convenient to adjust. In the tuner is turned expose the frequency of 87.50 MHz and a control voltage at the VT. It should be 2.1 V. If you close, you can try a miniature ferrite rod otvertochkoy twist in the coil and adjust the voltage of 2.1 V. If the voltage is always greater than necessary, it is necessary to further reduce the number of turns in the coil. If the voltage at the point of VT markedly less than 2.1 volts, you overdid it and you want to turn back into place. I have the grace came when I removed about a half turn (unfortunately tuning inductance with the ferrite core has a very small range of adjustment). When you tune into the very same 2.1 V, then try to go to 108MHz. At the point of VT should be about 6Volt. I was a little less by the way, but it is IMHO not a crime. Now you can finally cut off the excess wire and solder the coil in its place. Radio has already PLAY. Bad, but it should!
So, in practice, turned the voltage at the point at 87.5 MHz, VT 3 volts!, ??With the core of the Black coil should be in the middle position and have the freedom to adjust!!
More to break and remake does not have to!!!
Crank radio, first known to be a good tune on the wave, take a mini otvertochku, such as for hours, and begin to customize the second coil (which is white), twisting back and forth achieve the best result, and then adjusts the first coil (black, although a full chocolate I had a at 3 volts! at the point of VT) and least adjusts the last coil (green) by gentle moving apart / moving the turns and get pleasure from the work done!
Unfortunately, pictures do not, disassemble the new no mood and time, if someone does not understand - please send photos of the tuner-tknu what and where to do it!
Reconfiguring the remaining circuits.
- It is necessary to reconfigure the input LC-circuit. Fed to the appropriate coil and remove one turn. Solder back. The reception quality must now be considerably higher. Moving / pushing the turns of the circuit configuration can be changed and therefore the quality of reception. In fact, the input circuit is a bandpass filter with all the considerations and consequences.

-Next. Tune in a station manually with the naiotvratitelneyshim reception. And start to turn the ferrite rod coil-winding. According to the ideology of the reception should be improved by reducing the effect of iron on the winding. Yes there seems, in practice, the way it is! I do my best result was achieved with a fully torn off from the coil core. With this experience with the removal of a single turn coil which is built LC-circuit was not very successful. The inductance of the coil was too small and even a ferrite rod was not able to raise it to the required level. While this may be a feature of a particular instance and no more. In any case, I will describe how and what to do. In this case we are interested in is the winding, which is connected to the board with two pins varicap (This is a three-legged SMD-bony plates on the back side of the board). I have been a top coil on coil and its conclusions have been soldered to the board of the oscillator coil. Fed to the coil and the wind off a round with that winding. Then solder it back and donastraivaem ferrite rod ..

- Putting it all in reverse order, and .........
....... listen to the radio in the usual range
 

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Discussion Starter #18
Well, I've managed to find myself a spare unit for a good price. It is another addzest but as it'll be a spare I can perform the tuner tweaks without fear of ruining my radio. Watch this space for more info as and when the unit arrives. (probably some time next week as it is unlikely to be posted to me before monday)
 

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Hello Kei,

I have the DRX9255 Japanese Addzest model and have attempted the conversion to US frequency band with some success. Conversion to the European band would involve similar steps. There are many internet forums with people wanting to know how to do this, but few threads with people sharing first hand knowledge and success. While the Clarion and Addzest are very similar, dozens of differences on the circuit board design and tuner to make this a daunting task; more than I anticipated.

Since you already have two Addzest models, read on. The system controller IC is programmed and among many tasks acts as a divider network to control the PLL tuner IC. Initial destination area is set by a jumper located on the rear of the main PCB, opposite to the system controller. By moving a zero ohm resistor from JPN to USA near the system controller, it will bring pin 77 on the system controller from high (5 volts) to low (0 volts). It can also be moved other (EURO) to bring pin 77 to ½ VCC. This will effectively change the frequency range and spacing visible on the display.

Of note, there are two other jumper areas on the front of the main PCB marked USA. While the Clarion service manual makes no mention of these blank component areas, it does appear from the schematic that the traces are connected on the Clarion model. As such, I soldered two additional surface mount zero ohm resistors in place. No difference was observed.

At this point, you will still not be able to tune in any FM /AM frequencies because the front end tuner is different. Unfortunately, BL 1 880-1950B is discontinued and the schematic and component values are not indicated in the service manual. You can obtain data sheets for the individual Sanyo, Panasonic, and Toshiba IC’s and observe recommended circuit application and note differences of component values between USA and JPN design. Manufacturer's usually do not deviate, but this is an electrical engineering technical level. The easier route is to obtained an inexpensive Clarion model of similar vintage for parts and salvaged part 880-1950B. This is what I did. Unfortunately, the logic board obtained was mfg. 1994 and was rev 099-9967-03 instead of 099-9967-04 mfg 1996 and contained earlier generation Sanyo IC LA1192 instead of the improved LA1193. The earlier rev was different in other ways too. However, since the Pin-out was the same, I replaced the entire BL 1 880-1950B. FM now works with good reception. AM works marginally, no where near what it should be for a tuner of this caliber. Front end tuners are calibrated at the factory and are not easy to optimize without an oscilloscope or volt meter and signal generator. I have not tried to adjust any of the variable settings on the tuner yet. It is not really possible to adjust real time while in operation, once the shield is soldered in place and the tuner is reinstalled.

I still listen to AM talk radio in the car, often enough to be disappointed. I may try to obtain another parts deck for 099-9967-04 or try further experimentation, but am concerned because there are a number of component differences on the main PCB tuner area also. Without the Addzest service manual for direct comparison of component values against the Clarion Service manual it is difficult to know what should be further changed. I am curious if others have had better success.

If anyone has the Addzest service manual send me a PM for trade. I already have pictures and can post some soon.
 

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Discussion Starter #20 (Edited)
Cheers, that info will be a great help, by chance do you happen to know of any suitable clarion models from this era that can be butchered for parts? I've got a wanted ad on another forum for a broken clarion, but i think they are quite rare in the UK.

I think you may have trouble with an addzest service manual as it'll be in japanese scipt. I've got an addzest EXL owners manual and its mostly in kanji. I also have some bits of the mcintosh MX406 service manual, mainly circuit diagrams.

Some nice big pictures of the tuner board will be super.

Lastly, what are the IC numbers so i can get their datasheets? (I've got the sanyo LC7219 and Toshiba TA7372P datasheets already)
 
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