While cleaning my room, I stumbled upon a retro music player tucked away in a dusty corner. It was my Philips AZ302, a classic piece that had long been forgotten. Curious, I decided to turn it on and see if it still had some life left in it.
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| The image below represents the original Philips AZ302 for demonstration purposes, as I didn't capture clear photos before starting the modification. The fully modified version is shown later with my personal upgrades |
When I turned it on, to my surprise, it powered up flawlessly. It started in CD mode, so I switched to FM mode. While the FM mode activated, it sadly couldn’t capture any local stations. Next, I tried the MW mode and managed to tune into a station. However, something felt off—the frequency was incorrect. The station tuned at 1300 kHz, even though it should have been at 585 kHz, our local MW frequency.
To make matters more puzzling, the CD display remained on even when I switched to FM or MW mode. This behavior wasn’t normal; the display should turn off when switching to other modes. At that moment, I realized something was wrong with this player.
Finally, I shifted my attention to the AUX mode, a built-in feature of the Philips AZ302.
I plugged in my old, broken headphone jack as an AUX input and tested it with my phone. To my surprise, the CD mode disappeared immediately, and the player automatically shifted to AUX mode as soon as the cable was inserted. This was a pleasant discovery—the AUX feature worked perfectly! The sound was clear, well-amplified, and just as good as I’d hoped.
Encouraged by this, I removed the AUX cable and switched back to MW mode. However, the CD display turned on again, even in MW mode. It seemed like the player’s behavior still had some quirks to address.
It was clear to me—something was wrong with the player, and it needed fixing!
As I began brainstorming, another idea struck me: Why not modernize this retro player while I'm at it? We could bring it up to date by adding Bluetooth, SD card, and USB drive support. Nowadays, we have all-in-one modules that can offer these features. It seemed like the perfect opportunity to transition this classic device into a modern marvel.
But fixing and modernizing it required careful planning and consideration:
1. Identifying the Issues:
◦ Why does the previous mode stay active when switching to a new one?
◦ Why are FM and MW stations out of place? These problems needed to be diagnosed and resolved first.
2. Choosing a Modern Approach:
◦ Which module would be best for this player?
◦ How do I ensure the module integrates seamlessly into the existing system?
3. Power Supply:
◦ How do I provide the right power to the module without overloading the player’s existing components?
4. Placement Challenges:
◦ Where do I place the module and its controls?
◦ Should I add a switch for the module, or is it unnecessary?
◦ The player’s rounded shape limits placement options, as most modules are flat. How can I ensure the module works well despite this?
◦ What adjustments or trade-offs might I need to make for this upgrade to be successful?
These were the challenges ahead, but I was determined to breathe new life into this nostalgic device.
Solving the First Challenge: Identifying the Issues
To identify the root cause of the player’s malfunction, I first needed to open it up. After unscrewing all the screws (located on the bottom part of the player), I gained a clear view of the PCB. Upon inspection, I immediately noticed burned components near the AUX section and the mode-switching circuitry.
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| D106 (in Good condition), D108, also the diode below it in series mode, The transistor Below R136 |
At first glance, these components appeared to be Zener diodes, but they were not. This raised several questions:
• What exactly are these components?
• What are their values?
• Were other components in the series also damaged but visually intact?
• Why did these components burn out in the first place?
Identifying the Components
To identify the damaged parts, I took the following steps:
1. Cross-referencing Nearby Components:
Many PCBs reuse identical components across the board. I checked nearby areas to find similar-looking components with intact markings to determine their values.
2. Consulting a Service Manual or PCB Layout:
A stroke of luck! I found the service manual for the exact model, which included a detailed PCB layout and component list. This was invaluable for cross-referencing parts.
3. Testing with a Multimeter:
Using a multimeter, I tested the suspect components. Here’s what I found:
◦ One diode (1N4148) showed continuity in both directions, indicating it had shorted.
◦ Another diode was completely burned out with no power flow.
◦ A transistor (KTC 8050C) in the same circuit was also faulty.
◦ Interestingly, a third diode in the same area appeared burned but was fully functional upon testing. It only had soot from a nearby damaged component.
List of Damaged Components
• Three diodes (1N4148): Two were damaged, one was fine.
• One transistor (KTC 8050C): Faulty and needed replacement.
Root Cause Analysis: Why Did These Components Burn?
The circuit these components belonged to was part of the mode-switching system, which ensures only one mode (AUX, FM, or CD) is active at a time. The burned components explained why multiple modes were staying on simultaneously.
But why did they burn in the first place? Upon further inspection, I discovered the culprit:
• The player had a 120V/240V voltage selector switch hidden near the transformer. It had been accidentally set to 120V while the player was connected to a 240V mains supply. This caused an overvoltage scenario, damaging the sensitive switching components.
Plan for Repair
1. Replace the damaged components with new ones:
◦ Diodes (1N4148): Standard, widely available switching diodes.
◦ Transistor (KTC 8050C): Also widely used in switching circuits.
2. Ensure the 120V/240V selector switch is set correctly to prevent future overvoltage damage.
3. Test the entire switching circuit after replacing the components to confirm functionality.
Fixing the Misaligned FM and MW Stations
After addressing the burned components issue, I noticed that the FM and MW stations were not tuning correctly. This was likely due to the tuner becoming misaligned or misconfigured over time, a common problem in older devices.
Reconfiguring the Tuner
To fix this, I followed these steps:
1. Identify Local Station Frequencies:
First, I noted the frequencies of nearby stations for both FM and MW bands.
2. Adjusting the Tuner:
Below the tuner, I found four screws acting as potentiometers. These control the alignment of the tuner. With careful adjustments and trial and error:
◦ I rotated each screw slightly.
◦ After a few attempts, the player began tuning stations correctly.
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| Below the tuner, I found four screws acting as potentiometers |
This resolved the issue, ensuring the FM and MW bands were aligned properly.
Identifying Power Distribution Issues
Even after resolving the tuning problem, another issue surfaced. The player couldn’t reach full volume because the power supply was being distributed across all sections. This occurred due to the burned components, which had shorted, causing power leakage into multiple circuits. The amplifier couldn’t receive the required power to function optimally.
To address this, replacing the damaged components became a priority.
Preparing for Repairs and Upgrades
With the problems identified, I created a shopping list of necessary components for both repairs and upgrades:
1. 1N4148 x 5:
◦ Use: Replace the faulty diodes and keep extras for future needs.
2. KTC 8050C x 2:
◦ Use: Replace the damaged switching transistor and keep a spare.
3. Bluetooth + SD + USB + FM + AUX + Echo All-in-One Module x 1:
◦ Use: Upgrade the player with modern features.
4. 7805 Voltage Regulator x 1 + Heatsink:
◦ Use: Power the new module with a stable 5V supply from the player’s existing 15-16V.
5. 78M05 Voltage Regulator x 1 (Optional):
◦ Use: As a backup if the 7805 isn’t ideal, since it doesn’t require a heatsink.
6. SPDT 4-Leg Switch:
◦ Use: Add manual control to toggle the module’s power and ensure proper AUX mode switching.
7. Two Screws for Module Placement:
◦ Use: Securely mount the new module inside the player.
8. Cello Tape:
◦ Use: Insulate connections and secure wires.
9. Ribbon Wires (10-Wire Ribbon):
◦ Use: For clean and organized wiring of the module and additional components.
Restoring and Upgrading the Philips AZ302
Market Run and Surprising Finds
To tackle the player’s issues and begin its upgrade, I went to the market with a detailed list of components. While shopping, I stumbled upon a resistor kit that caught my attention. It included 150 resistors (30 different values, 5 of each) ranging from 10Ω to 470kΩ—all for just 50 INR! These would come in handy for future projects.
After gathering the needed components and my unexpected treasure, I returned home ready to dive in.
So all components costs me arround RS 200 (INR)
Repairing the Player
Replacing the Burned Components
The first task was to replace the burned components:
1. 1N4148 Diodes: These were SMD diodes, but since I only had standard diodes, I adapted them by bending and trimming the legs to fit the SMD footprints.
2. KTC 8050C Transistor: I carefully replaced this as it was crucial for switching the modes properly.
After replacing these components, I tested the player. To my delight, the player worked perfectly!
• Switching modes now correctly powered off the unselected ones.
• The amplifier regained full power, and the volume was crystal-clear even at maximum.
Planning the Module Upgrade
Now that the player was restored to its original functionality, I focused on upgrading it with a Bluetooth, USB, SD card, FM, and AUX module.
Placement Challenges
The player’s rounded design made placement tricky. After considering several options, I decided:
1. Bottom of the Player: The right side of the bottom was perfect for the module.
◦ Trade-offs:
▪ USB access would be difficult.
▪ The remote might not work seamlessly, but I tested aiming the remote at the bottom and it worked fine.
▪ SD card placement was fully accessible, which was my main priority.
2. Left Side Upper Round Space: Near the Dynamic Bass button, I marked space for a SPDT switch to toggle the 5V regulator and AUX short.
Innovative Solutions
Regulator Placement
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| Empty place on PCB for regulator |
Inside the player, I found an unused area on the PCB, which was ideal for mounting the 7805 regulator:
• Mounting Hack:
◦ I drilled a small hole in the PCB to secure the regulator with a screw.
◦ Nearby, I noticed a ground connection. Instead of using wires, I scratched the PCB to expose the copper trace and soldered the regulator's middle leg directly to it.
This saved me wiring effort and maintained a clean layout!
Completing the Connections
With the regulator mounted and the cuts for the module and switch perfectly placed, it was time to tackle the wiring. This was the most delicate part of the process:
Powering the Regulator and Module
The power for the 7805 regulator needed to be carefully selected to avoid overloading existing components:
1. Testing Power Points:
◦ I identified two potential power sources:
▪ Near the bridge rectifier.
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| BAT+ is VCC of rectifier |
▪ Near the amplifier.
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| 14 Leg Chip is amplifier, first TOP 2 are VCC |
◦ The amplifier point was ruled out due to noise concerns, as any noise from the amplifier could get amplified further.
◦ I chose the point near the bridge rectifier, which was stable and noise-free.
2. Wiring the Regulator:
◦ Input from the bridge rectifier was connected to the regulator through the SPDT switch, allowing me to power off the regulator when the module wasn’t in use.
◦ The output of the regulator was connected to the Bluetooth module.
Reducing Noise
After powering on the module, I noticed significant noise interference. To resolve this:
1. I avoided using the noisy ground near the regulator.
2. Instead, I connected the module’s power ground to the AUX ground, which is inherently less noisy.
3. I left the Speaker Ground of module unconnected, because we have common ground of power so no need of two grounds.
Finding the AUX Short
The AUX short was critical for forcing the player into AUX mode.
1. I attempted to identify the AUX short points near the AUX jack by shorting various points, but these attempts caused minor short circuits and sparks, risking further damage.
2. To avoid burning any components, I chose a safer workaround:
◦ I left the AUX short pin open.
◦ This "fake" AUX pin was sufficient to force the player into AUX mode.
Testing the Restored Player
After completing all connections, it was time to test the upgraded player:
1. Power and Mode Switching:
◦ The SPDT switch allowed me to toggle the regulator on and off, ensuring power was conserved when the module wasn’t in use.
◦ Mode switching on the player worked perfectly, with no interference between modes.
2. Module Performance:
◦ The Bluetooth worked seamlessly, offering excellent sound quality.
◦ The SD card played without issues, and I didn’t miss USB support as much since I rarely use it.
◦ The remote worked well, despite the module being mounted at the bottom of the player.
3. Built-in FM vs. Module FM:
◦ The module’s FM reception was poor despite using the built-in player’s antenna.
◦ The player’s built-in FM, however, provided excellent reception and clarity, justifying my decision to retain it.
4. Audio Quality:
◦ The player’s amplifier delivered crystal-clear, rich sound.
◦ Bluetooth, AUX, and SD card playback maintained high audio fidelity.
Final Output:
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| The fully restored and upgraded Philips AZ302 - A perfect blend of vintage charm and modern functionality |
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| Bottom of Philips AZ302, with fixed module! |
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| Philips AZ302 with module remote! |
Final Thoughts
With this restoration and upgrade, my Philips AZ302 transformed from a dusty retro player into a versatile, modern audio powerhouse. The built-in FM, coupled with the added Bluetooth and SD card support, created the perfect blend of vintage and contemporary features.
If you’re considering upgrading your old player, I hope this journey inspires and guides you. It’s an amazing feeling to breathe new life into something old while retaining its original charm!
Would you like to learn how to do this for your own player? Share your thoughts, or feel free to ask questions below!
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The Story Behind My Philips AZ302
This player, a Philips AZ302, has been a part of my life since 2007-09. I received it as part of a government initiative in India for the visually impaired. Being classified under PwBD (Persons with Benchmark Disability) due to my high myopia, I was provided with this player to listen to educational materials. However, there was one major issue—no CDs were ever provided for this player, nor was there any mechanism to easily obtain them in my village.
Living in a remote area without access to modern technology at the time, I couldn't use the player for its intended purpose of education. Instead, I explored its FM and MW capabilities, which became my gateway to the world of sound and music. Over the years, I received only three CDs: a collection of Bhim Geete (songs about Dr. B.R. Ambedkar), an old songs remix album, and a 2014 CD with about 60 songs.
In 2013-14, I discovered the AUX feature. With nothing but broken earphone cables, I crafted my first AUX cable and used it with my Nokia C101. Later, I connected it to my computer's line-out for an even better experience. For five years, this player served as my companion for music and sound exploration.
Fast forward to 2016, during my engineering days, I attempted to clean the player and unknowingly switched its power mode from 240V to 120V. This caused some components to burn out, though I didn’t notice it back then because the AUX mode was still functioning perfectly.
After years of disuse, this player sat collecting dust, until now. I decided to not only repair it but also upgrade it into a modern device that reflects my creative approach to tackling challenges.
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PCB Images:
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