I am familiar with this Dynamic PET board, it is the same as the one in my PET.
Daver2 noted that the 4116 and 8116 DRAMs are the same. Sometimes they also go by other numbers too, Intel for example made a D2117, that is the same part.
Your particular DRAM IC's look very beautiful and the board looks like it will clean up very well. There is also little rust (if any) on the power transformer's lamination stack, so this PET, apart from the dust must have been stored in very dry conditions.
If the CRT heater was going, it means that at that time at least, there was AC power coming from the power transformer to the VDU, and that the VDU's own regulated DC supply was probably working. The VDU circuitry is usually fairly reliable, the usual cause for it not lighting up is a fault on the main board, where the VDU does not receive the H.Drive signal, which it requires for the generation of the high voltages to run the CRT.
The first move in the repair is to make sure the main board's power supplies are working as you are doing. Re-seat the IC's in case there is a bad IC socket connection and after that confirm the CPU is running and look to see if the board is generating the H & V drive pulses for the VDU on the scope. The IC sockets in the PET are not the most wonderful design and rely on a single wipe of one side of the IC pin only, the other side of the IC pin abuts the plastic.
If you tuned out later to have a RAM problem, it would be a shame to remove any of those IC's by mistake. Where any of the RAM outputs are stuck high or low, this prevents the computer from booting and creates a black screen. Though in this case, if you look during the boot up (if all else was normal) there is a flash of garbled characters on the screen as the 555 reset circuit operates.
If you need it there is some information in this article about the DRAM in the dynamic PET, how it operates, and remarks about how to interpret tests to find the faulty IC's. Also 20 or so scope recordings of the DRAM support circuitry that can help in fault finding:
There is a program there at the end of the article, to burn into a TMS2532JL ROM which has memory fill and memory test firmware. If memory below 0400h is working and supporting BASIC you can run those programs without the hardware adapter in the article to check the DRAM from 0400h to 7FFFh.
But there are also various PET-testers too, which are easier & helpful designed by Daver2 and Nivag.
With any luck though, your lovely ceramic DRAM IC's will be ok.