Sanyo AVM-2507
Sanyo AVM-2507 CRT RGB mod
The Sanyo AVM-2507 is a 25" color CRT television introduced in the mid-90s.
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This set is RGB moddable. I do not have pictures of this set yet. However, below instructions should work. Also, the same instructions should work for the below models.
- Sanyo AVM-2507
- Sanyo AVM-2508
- Sanyo DS25730
Contributors
Thank you to everyone who contributed to this guide:
CRT safety
Caution
You can die doing this! So read carefully! CRT TV is not a toy. Do not open a CRT TV. If you don't have any prior knowledge about handling high voltage devices, this guide is not for you. CRT TV contains high enough voltage (20,000+ V) and current to be deadly, even when it is turned off.
Plan of attack
Manuals and Datasheets
- Sanyo AVM-2507 Service Manual
- Sanyo LA76070N Datasheet (Jungle)
- Mitsubishi M37272M8-100SP Datasheet (OSD)
Specs
- Year:
- Jungle Chip: Sanyo LA76070N
- OSD Chip: Mitsubishi M37272M8-100SP
- Screen Size: 25"
RGB mux diagram
Prepare the mux diagram. If you are building your own circuit, this diagram should help.
Calculating the RGB external resistor value
Love it when we can put theories to use! Formula from our theory page!
We find out using ohms law, this CRT is using 0.5Vp-p. How?
Vp-p = 5V x (560/(5600+560)) = 5V x 0.0909 = 0.45V
RGB external resistor value
= (0.5 x (5600 + 75) - (75 x 5)) / (5 - 0.5)
= (0.5 x 5675 - 375) / 4.5
= 2462 / 4.5
= 550Ω
560Ω resistors should do the job.
Performing the mod
Now that you roughly know what needs to be done, prepare for the mod. Place the board on a comfortable place. Make sure you are not putting pressure on the flyback or other components.
STEP 1: Remove the following components
Remove the following components. RGB resistors to the ground. Measure twice and mark before you remove.
- R842 (560Ω)
- R843 (560Ω)
- R844 (560Ω)
STEP 2: Connect RGB, Blanking
STEP 3: Blanking diode
To prevent current from flowing back into the OSD and causing interferences in RGB mods, it's necessary to include a diode in the blanking line. The absence of this diode is the main cause of such issues.
STEP 4: Sync and Audio
Sync and Audio can be connected to Video 2 input. You can also connect sync to the S-Video luma input to reduce the RGB shift.
STEP 5: Build your mux board
This mod uses the RGB mux board. This is optional, but will make your mod easier and stable. You can also create the circuit presented in the schematics above without the board. Please also checkout the mux calculator to play with your own values.
| On Sanyo CRT Chassis | AVM-2507 |
|---|---|
| CRT RGB inline resistor | 5.6kΩ |
| CRT RGB ground resistors removed | 560Ω |
| 0.1μF caps replaced | No |
| Add RGB diodes on chassis | No |
| Add blanking diode on chassis | No |
| RGB mux board | AVM-2507 |
|---|---|
| Mux board RGB termination (R1, R2, R3) | 75Ω |
| Mux board RGB inline resistors (R4, R5, R6) | 680Ω |
| Mux board Audio LR (R7, R8) | 1kΩ |
| Mux board blanking diode (R9) | 1N4148 |
| Mux board blanking ground resistor (R10) | open |
| Mux board blanking resistor (R11) | 1kΩ |
Compatible mux boards:
STEP 6: Service Menu and User Menu Adjustments
To attain the appropriate equilibrium between composite/s-video input and RGB input, numerous adjustments to both the Service Menu and User Menu were required for this set. Once set, you don't have adjust these when you switch inputs.