(This is part of an ongoing effort to document the various CRT monitors and televisions that I acquire, with information that may be of relevance to others who Google the same model!)
This is a fairly bulky 27" curved television set, and one of the rare instances where it feels as back-heavy as it does front-heavy. It has spring-loaded side handles to make lugging it around marginally more bearable. The set weighs 88 pounds and measures 29.5 x 23.2 x 18.7 inches (852 x 692 x 580 mm). Internally it houses 5W stereo speakers. No component inputs, but it does have three composite inputs on the back and a fourth on the front, as well as s-video. The s-video signal is shared with the bottom-most composite input (Video 3) on the back. So for audio out while on the s-video input, you will want to connect the stereo cables to the bottom set of jacks on the back. There is also a composite output to feed another device.
I picked up this set boxed as new old stock for $1 from an estate sale. The weight took me by surprise in the bulky packaging. I knew before acquiring it that it lacked component input, but figured it would make a practical setup for multi-cart systems such as the Hyperkin RetroN 3, which supports s-video output and NES, SNES and Genesis inputs. Unfortunately, the tube (even as new stock) suffers a small degree of horizontal barrel distortion at the edges, which is most noticeable in side-scrolling games and videos where the edges look like they are being unrolled from a spindle. This is the same symptom that plagues many flat and flat-inspired CRTs common in the mid-late 2000s. Out of the box, overscan was not bad with about 7 pixels at the top, 3 at the bottom and 2 on the left.
This set is very similar to other 24" and 27" models released from 2003-2004 including the AT2702 and AT2708. Apex Digital was a Canada-based facility that distributed many budget line TVs and DVD players in the mid-2000s, notably for Walmart. The sets were manufactured by Sichuan Changhong Electric in China, and there were substantial losses incurred in the mid-2000s due to antidumping duties. Apex is also notable for producing the first consumer DVD sets to natively support MP3 encoded discs in 2002.
The box it came in reads:
APEX DIGITAL - AT2704S 27" Stereo Color TV
- 27" Screen
- 181 Channel Tuner
- S-Video Input
- Front AV Stereo Input (1)
- Rear AV Stereo Inputs (3)
- Rear AV Stereo Output (1)
- Full Function Remote Control
- Selectable Picture Modes
- Channel Recall
- Parental Control
- Trilingual OSD (English, Spanish, French)
- 29 1/2"W x 23 1/5"H x 18 7/10"D
- Chasis: CH-10C
Service Mode Adjustments
Entering service mode on the AT2702, AT2704 and AT2708 models can be done as follows:
- With the power on, decrease the volume until it reads "00" on screen.
- Tap the Mute button on the remote control so that "MUTE" appears on the screen.
- Press and hold the Mute button on the remove, and simultaneously hold in the Menu button on the TV itself.
- After several seconds, the service menu will appear.
The default values on my set, which may vary by model and calibration, were as follows:
| Menu Page | Option | Value | Notes |
|---|---|---|---|
| 0 | AFW: 240Khz | 1 | |
| 0 | IF-PLL | 1 | |
| 0 | AFA: Inside | 1 | |
| 0 | AFA: Below | 1 | |
| 0 | AGC Over F | 7 | |
| 0 | IFS | 0 | |
| 0 | MOD | 0 | |
| 1 | Fixed Aud. | 1 | |
| 1 | Sound Mute | 0 | |
| 1 | Auto Limit | 0 | |
| 1 | FLNG1 | 0 | |
| 1 | FLNG2 | 0 | |
| 1 | FLNG3 | 0 | |
| 1 | Opt. Stereo | 1 | |
| 1 | Opt. Spatal | 1 | |
| 2 | Blank HOB | 0 | |
| 2 | De InterLa | 0 | |
| 2 | H Shift | 43 | |
| 2 | H Shift-50 | 31 | |
| 2 | E/W Wide | 43 | |
| 2 | Parabola | 29 | |
| 2 | E/W Corner | 37 | |
| 2 | Trapzium | 25 | |
| 2 | OSD H. Pos | 3 | |
| 3 | Ver. Mode | 0 | |
| 3 | Ver. Out | 0 | |
| 3 | Overscan | 1 | |
| 3 | Ver. Protec | 0 | |
| 3 | Blank Fix | 0 | |
| 3 | Ver. Dividr | 0 | |
| 4 | V. Half | 0 | |
| 4 | V. Center | 37 | |
| 4 | V. Center50 | 31 | |
| 4 | V. Amp | 19 | |
| 4 | V. Amp-50 | 31 | |
| 4 | S. Correct | 16 | |
| 4 | V. Shift | 31 | |
| 4 | V. Shift-50 | 31 | |
| 4 | V. Zoom | 25 | |
| 4 | V. Scroll | 31 | |
| 5 | Whit P. Red | 31 | |
| 5 | Whit P. Gre | 32 | |
| 5 | Whit P. Blu | 21 | |
| 5 | AKB | 1 | |
| 5 | Y-Delay | 8 | |
| 5 | Cathod Lev. | 5 | |
| 6 | Blue Stret | 1 | |
| 6 | Black Stre | 1 | |
| 6 | Y-Value | 0 | |
| 6 | Skin Angle | 0 | |
| 6 | Skin Tone | 1 | |
| 6 | B. B. Level | 40 | |
| 7 | ACL | 1 | |
| 7 | CB | 0 | |
| 7 | CMB | 0 | |
| 7 | BPS | 0 | |
| 7 | MAT | 0 | |
| 7 | Opt. DW4MIN | 1 | |
| 7 | Opt. OVPT | 1 | |
| 7 | Opt. BBK | 1 | |
| 7 | Auto Adjst | 0 | |
| 8 | Sub. Bright | 31 | |
| 8 | Av. Prescal | 75 | |
| 8 | Cntrst Max | 63 | |
| 8 | Cntrst Mid | 31 | |
| 8 | Cntrst Min | 0 | |
| 8 | Color Core | 31 | |
| 8 | Sub. Tint | 28 | |
| 9 | BCO | 1 | |
| 9 | XA. XB | 1 | |
| 9 | STB | 1 | |
| 9 | POC | 0 | |
| 9 | CM2. 1. 0 | 0 | |
| 10 | VIM | 1 | |
| 10 | STM | 0 | |
| 10 | HCO | 1 | |
| 10 | EVG | 0 | |
| 10 | PRD | 1 | |
| 10 | COR | 1 | |
| 11 | OSO | 1 | |
| 11 | CS1. CS0 | 0 | |
| 11 | AST | 1 | |
| 11 | FFI | 0 | |
| 11 | EBS | 1 | |
| 11 | FCO | 0 | |
| 12 | Opt. AV2 | 1 | |
| 12 | Opt. AV3 | 1 | |
| 12 | Opt. YCbCr | 0 | |
| 12 | Opt. Color | 0 | |
| 12 | Opt. V-Chip | 1 | |
| 12 | Opt. CCD | 1 | |
| 12 | Opt. Pwr-On | 0 | |
| 12 | Srch Speed | 0 | |
| 12 | ROM Correc | 0 | |
| 12 | MSP/TDA | 0 |
There are still a lot of analog adjustments noted in the service manual, but the on-screen servicing menu offers a lot of options itself, albeit cryptically. I noticed one option for YCbCr exists in the ROM, indicating at least in some iterations of the chassis and models component input was integrated, and likely not a difficult mod to make by piggybacking off the video chip.
The biggest notable defect in the set is the horizontal distortion that can occur on the edges where the picture appears to be rolling in, rather than perfectly linear. Of the adjustment options, reducing "E/W Wide" (East/West Wide) can lessen the effect. If you don't mind some side letterboxing, you may prefer to reduce this value enough where the distortion goes away without other detrimental effects. It's easy to experiment with this adjustment while running 240p Test Suite or any side-scrolling game to arrive at a desirable output. The "XA. XB" option can also immediately divert the set to monochrome, when setting the value to 2.
Internals
The bulky case with an 8.5" flat top surface can be removed with about eight screws and then slides right off. The picture tube is a very popular Thomson branded A68AEG25X01. The same picture tube can be found in the highly regarded JVC D-Series (AV-27230, etc).
The PCB is fairly accessible, with two screws holding in the plastic bracket that can then slide out. It consists of a power PCB and main logic PCB, along with the video I/O and neck board PCBs. Identified ICs include:
- OM8839PS - Video Controller
- TDA9859 - Hi-Fi Audio Processor
- TDA7057AO - 2x3 Stereo BTL Audio Output Amp
- CH04T1009
- TDA4605-3 - Control IC for Switched-Mode Power Supplies
Documents
My set came with the original manual and remote still sealed. I found the manual exists online, and was able to locate an AT2702S service manual, which for most purposes should be quite similar. The schematic section of the service manual is buggy and renders in a light green with large blocks obscuring portions.