Here are some miscellaneous Links that may or may not come in handy at some point. FYI, If you decide to attempt any modifications to your HTX-252, you are doing so at your own risk.
HTX-252/Albrecht AE540 Service Manual
Information on expanding the TX of the HTX-252 to 136-174MHz (I have not personally tried this.)
There are a few mods online where folks have replaced the display light bulbs with LEDs. One of my back light bulbs is burnt out so this may be my next mission in keeping this trusty old rig fully operational. More on that coming soon…